V8 VUM

Once again I am hoping for your help!

OK ECM -E38 on an LS7 - all new

Car - Ultima

Original problem - no throttle response at all :
Evidence found: reference voltage dragged down to 1.5 volts -
Resolution: disconnect four pin plug from Alternator to ECM - problem gone!

Cause? - faulty new Alternator it appears!!!

Replacement Alternator fitted - plugged in and fault does not occur - throttle response as expected - GREAT

HOWEVER - no charge!

Either the ECM duty cycle (grey wire) circuit and Request (orange wire) circuit compromised in ECU (by the faulty alternator?) or I have missed something in the wiring from the ECU to the car?

Where does the ECU get its signal from to kick the Alternator to charge state (request)?
Same for monitoring the 12 volt threashold (duty cycle???) ?

When the loom came I found a bunch of wires (presumably to be connected to the main car loom for Tacho, speedo etc etc), and all had hand-written labels - fine!

Two had me scratching my head - 12 volt for A/C request, and A/C request signal. The request signal was easy - so linked to my heater/AC controls. The other one??????? I don't know what it is for (PINK wire)

No idea if this had been mislabelled. (and the word A/C and Alt are easy to get miswritten)

so...either the ECM is screwed, or there is something I have not done ref wiring.

Please help, this saga has been going on for well over 2 months!

cheers - & hoping

Keith

songman3

Here's a diagram of the charging system



hope this helps

Bill Dearborn

Here is a picture of the schematic and a description of how the system is supposed to work along with diagnostic codes that might come up in the ECM. Not sure what ECM you have compared to a C6 but the codes might help if you can see them.



[IMG]file:///C:/Users/BillD_2/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif[/IMG]


Charging System Description and Operation
Generator

The generator features the following major components:
• The delta stator
• The rectifier bridge
• The rotor with slip rings and brushes
• A conventional pulley
• The regulator

The slip ring and the frame are liquid cooled.
The generator features permanently lubricated bearings. Service should only include tightening of mount components. Otherwise, replace the generator as a complete unit.
Regulator

The voltage regulator controls the rotor field current in order to limit the system voltage. When the field current is on, the regulator switches the current on and off at a rate of 400 cycles per second in order to perform the following functions:
• Radio noise control
• Obtain the correct average current needed for proper system voltage control

At high speeds, the on-time may be 10 percent with the off-time at 90 percent. At low speeds, the on-time may be 90 percent and the off-time 10 percent.
Circuit Description

The generator provides voltage to operate the vehicle's electrical system and to charge its battery. A magnetic field is created when current flows through the rotor. This field rotates as the rotor is driven by the engine, creating an AC voltage in the stator windings. The AC voltage is converted to DC by the rectifier bridge and is supplied to the electrical system at the battery terminal.
When the engine is running, the generator turn-on signal is sent to the generator from the engine control module (ECM), turning on the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F terminal is connected internally to the voltage regulator and externally to the ECM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM that a problem exists. The ECM monitors the generator field duty cycle signal circuit. The system voltage sense circuit receives B+ voltage that is Hot At All Times through the HORN/ALT SENSE fuse in the underhood junction block. This voltage is used by the regulator as the reference for system voltage control. On vehicles that use a sense circuit connected to the voltage regulator, this circuit must be operating properly for the charging system to work correctly, when there is a charging system concern all circuits at the generator should be tested.
Charging System Messages

The driver information center (DIC) displays a charging system message the when the following occurs:
• The engine control module (ECM) detects that the generator output is less than 11 volts or greater than 16 volts. The DIC receives a serial data message from the ECM requesting illumination of a charging system message.

The instrument panel cluster (IPC) determines that the system voltage is less than 11 volts or greater than 16 volts. The IPC receives a serial data message from the body control module (BCM) indicating the system voltage.

BATTERY SAVER ACTIVE
The DIC displays the BATTERY SAVER ACTIVE message when the BCM reduces or disables the performance of some vehicle systems in order to reduce the load on the charging system. The DIC receives a serial data message from the BCM requesting illumination.
BATTERY VOLTAGE HIGH
The DIC displays the BATTERY VOLTAGE HIGH message when the IPC determines that the system voltage is greater than 16 volts. The IPC receives a serial data message from the BCM indicating the system voltage.
BATTERY VOLTAGE LOW
The DIC displays the BATTERY VOLTAGE LOW message when the IPC determines that the system voltage is less than 11 volts. The IPC receives a serial data message from the BCM indicating the system voltage.
SERVICE CHARGING SYSTEM
The DIC displays the SERVICE CHARGING SYSTEM message when the ECM detects a malfunction with the generator output. The IPC receives a serial data message from the ECM requesting illumination.
SERVICE ELECT SYSTEM
The DIC displays the SERVICE ELECT SYSTEM message when the ECM detects a malfunction with the generator output. The IPC receives a serial data message from the ECM requesting illumination.

DTC P0562 (ECM)
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptor
DTC P0562: System Voltage Low

Diagnostic Fault Information



IGN I= P0562= P0562 =-- = --
Ground= --= P0562= --= --

Circuit/System Description

The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.
Conditions for Running the DTC

• The vehicle speed is above 8 km/h (5 mph).
• The system voltage is between 9.5-18 V.

Conditions for Setting the DTC

The ECM detects a system voltage below 10 V for 5 seconds.
Action Taken When the DTC Sets

DTC P0562 is a C type DTC.
Conditions for Clearing the DTC

DTC P0562 is a C type DTC.
Diagnostic Aids

• A low voltage DTC set in multiple modules indicates a concern in the charging system.
• A low voltage value in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification

1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.5 V.

· If not within the specified range, refer to Charging System Test

2. Observe the scan tool ECM Ignition 1 Signal parameter. The reading should be between 12.6 and 15.5 V.
Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the ECM.
2. Ignition OFF, and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 Ω between the ground circuit terminals listed below and ground.
• Terminal 73 X1 (LS3/LS7)
• Terminal 73 X2 (LS9)
• Terminal 73 X3 (LS9)

If greater than the specified range, test the ground circuits for an open/high resistance.

3. Ignition On, verify that a test lamp illuminates between the IGN/B+ circuit terminals listed below and ground:
• Terminal 18 X1 (LS3/LS7)
• Terminal 19 X1 (LS3/LS7)
• Terminal 20 X1 (LS3/LS7)
• Terminal 47 X1 (LS3/LS7)
• Terminal 20 X1 (LS3/LS7)
• Terminal 18 X1 (LS9)
• Terminal 19 X1 (LS9)
• Terminal 20 X1 (LS9)
• Terminal 13 X2 (LS9)

4. If all circuits test normal, replace the ECM.
Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming

DTC P0563 (ECM)
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC P0563 : System Voltage High

Diagnostic Fault Information

IGN I= P0562= P0562 =-- = --
Ground= --= P0562= --= --











IGN I
P0562
P0562
--
--
Ground
--
P0562
--
--

Circuit/System Description

The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.
Conditions for Running the DTC

• The vehicle speed is above 8 km/h (5 mph).
• The system voltage is between 9.5-18 V.

Conditions for Setting the DTC

The ECM detects a system voltage above 16 V for less than 1 second.
Action Taken When the DTC Sets

DTC P0563 is a C type DTC.
Conditions for Clearing the DTC

DTC P0563 is a C type DTC.
Diagnostic Aids

• A high voltage DTC set in multiple modules indicates a concern in the charging system.
• A possible cause of this DTC could be overcharging with a battery charger or jump starting.
• A high voltage value in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
• Circuit Testing
• Connector Repairs
Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification

1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.5 V.

· If not within the specified range, refer to Charging System Test

2. Engine running, observe the scan tool ECM Ignition 1 Signal parameter.The voltage should be between 12.6 and 15.5 V.

· If not within the specified range, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming

DTC P0621
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC P0621: Generator L-Terminal Circuit

Diagnostic Fault Information











Generator Turn ON Signal
P0621
P0621
P0621
P0621

Circuit/System Description

The engine control module (ECM) uses the generator turn on signal circuit to control the load of the generator on the engine. A high side driver in the ECM applies a voltage to the voltage regulator. This signals the voltage regulator to turn the field circuit ON and OFF. The ECM monitors the state of the generator turn on signal circuit. The ECM should detect low voltage on generator turn on signal circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage on the generator turn on signal circuit. The ECM performs Ignition ON and RUN tests to determine the status of the generator turn on signal circuit.
Conditions for Running the DTC

Ignition ON Test
• No generator, crankshaft position (CKP) sensors, or camshaft position (CMP) sensor DTCs are set.
• The ignition is in RUN position.
• The engine is not running.

Run Test
• No generator, CKP sensors, CMP sensor DTCs are set.
• The engine is running.

Conditions for Setting the DTC

• During the Ignition ON test, the ECM detects high voltage on the generator turn on signal circuit for 5 seconds.
• During the RUN test, the ECM detects low voltage on the generator turn on signal circuit for 15 seconds.

Action Taken When the DTC Sets

DTC P0621 is a C Type DTC.
Conditions for Clearing the DTC

DTC P0621 is a C Type DTC.
Diagnostic Aids

On vehicles equipped with a sense circuit connected to the voltage regulator. This circuit must have voltage for the charging system to operate properly. This circuit is used as a reference to control system voltage. All circuits must be tested at the generator before replacing any components. Refer to system schematic to confirm if the vehicle being serviced uses the sense circuit as part of the charging system.
Reference Information

Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the generator.
2. Ignition OFF, test for B+ between the generator sense circuit terminal D and ground.
·
· If less than the specified range, test the generator sense circuit for a short to ground, an open/high resistance.

3. Ignition ON, test for less than 1 volt between the generator turn on signal terminal B and ground.

· If greater than the specified range, test the generator turn on signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Engine running, test for greater than 3.5 V between the generator turn on signal and ground.

· If less than the specified range, test the generator turn on signal circuit for a short to ground, an open/high resistance. If the circuit tests normal, replace the ECM.

5. If the circuit tests normal, replace the generator.
Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• Generator Replacement
• Control Module References for ECM replacement, setup, and programming

DTC P0622
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC P0622: Generator F-Terminal Circuit

Diagnostic Fault Information











B+
P0622
P0622
--
--
Generator Field Duty Cycle Signal
P0622
P0622
P0622
P0622

Circuit/System Description

The engine control module (ECM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5-95 percent.
Conditions for Running the DTC

• No generator, crankshaft position (CKP) sensors, or camshaft (CMP) sensor DTCs are set.
• Ignition ON engine OFF, for the Ignition ON test.
• Engine is running, engine speed less than 3,000 RPM for the RUN test.

Conditions for Setting the DTC

• Ignition ON engine OFF, the ECM detects a PWM signal that is greater than 65 percent for 5 seconds.
• Engine running, the ECM detects a PWM signal that is less than 5 percent for 15 seconds.

Action Taken When the DTC Sets

DTC P0622 is a C type DTC.
Conditions for Clearing the DTC

DTC P0622 is a C type DTC.
Reference Information

Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification

Engine running, observe the scan tool ECM GEN-F Terminal Signal parameter. The parameter should read between 10-95 percent.
Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the generator.
2. Verify that a test lamp illuminates between the generator output B+ circuit terminal B and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition ON, verify the scan tool ECM GEN-F Terminal Signal parameter displays less than 5 percent.

• If greater than the specified range, test the signal circuit terminal C for a short to voltage. If the circuit tests normal, replace the ECM.

4. Install a 3A fused jumper wire between B+ and the signal circuit.

5. Verify the scan tool ECM GEN-F Terminal Signal parameter displays greater than 95 percent.


· If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.


6. If the circuit tests normal replace the generator.
Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• Generator Replacement
• Control Module References for ECM replacement, setup, and programming

DTC P0622
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor
DTC P0622: Generator F-Terminal Circuit

Diagnostic Fault Information











B+
P0622
P0622
--
--
Generator Field Duty Cycle Signal
P0622
P0622
P0622
P0622

Circuit/System Description

The engine control module (ECM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5-95 percent.
Conditions for Running the DTC

• No generator, crankshaft position (CKP) sensors, or camshaft (CMP) sensor DTCs are set.
• Ignition ON engine OFF, for the Ignition ON test.
Engine is running, engine speed less than 3,000 RPM for the RUN test.

Conditions for Setting the DTC

• Ignition ON engine OFF, the ECM detects a PWM signal that is greater than 65 percent for 5 seconds.
• Engine running, the ECM detects a PWM signal that is less than 5 percent for 15 seconds.

Action Taken When the DTC Sets

DTC P0622 is a C type DTC.
Conditions for Clearing the DTC

DTC P0622 is a C type DTC.
Reference Information

Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification

Engine running, observe the scan tool ECM GEN-F Terminal Signal parameter. The parameter should read between 10-95 percent.
Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the generator.
2. Verify that a test lamp illuminates between the generator output B+ circuit terminal B and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition ON, verify the scan tool ECM GEN-F Terminal Signal parameter displays less than 5 percent.

· If greater than the specified range, test the signal circuit terminal C for a short to voltage. If the circuit tests normal, replace the ECM.


4. Install a 3A fused jumper wire between B+ and the signal circuit.

5. Verify the scan tool ECM GEN-F Terminal Signal parameter displays greater than 95 percent.
· If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.


6. If the circuit tests normal replace the generator.
Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• Generator Replacement
• Control Module References for ECM replacement, setup, and programming

Sorry about the inability for the forum to handle tables, hopefully you will be able to figure out the rows and columns.

Bill

ZenOhSix

Good luck; I want to see pictures of the car!

I always wanted to build one.