Allison

CIRCUIT DESCRIPTION:
The TCM receives input on throttle position from either a TPS or a signal transmitted by the engine electronic controls.

Vehicles not equipped with electronically-controlled engines have a TPS attached to the engine fuel control linkage. The TPS continuously sends the exact throttle position to the TCM.

The TPS is a sliding resistor sensor (potentiometer) actuated by a mechanical linkage. The TCM delivers a constant voltage to one terminal of the TPS resistive strip. The other TPS terminal connects to ground. The resistor contacts of the TPS are connected to provide a regulated voltage signal input to the TCM.

When actuated by the mechanical throttle cable, the contacts of the resistor move along the resistive strip. As the contacts slide along the resistive strip, a voltage is sent to the TCM. At each increment of 0.178 mm (0.007 inch) along the resistive strip, the contacts deliver a different voltage to the TCM. The different voltages are interpreted as throttle sensor movement. The TCM converts travel distance (mm) into throttle opening percentage.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC P0122 is stored in the TCM history.
2. The TCM uses the default throttle value, based on engine torque and speed.
3. The TCM forces Variable Modulated Main off.
4. The TCM inhibits Torque Converter Clutch (TCC) engagement.
5. The CHECK TRANS light illuminates (non-OBD II strategy).

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

DIAGNOSTIC AIDS:
Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
3. Poor terminal tension.
4. A chafed wire.
5. A broken wire inside the insulation.

When diagnosing for an intermittent short or open circuit condition, massage the wiring harness while watching the test equipment for a change.

You may have to drive the vehicle in order to experience a fault.

CIRCUIT DESCRIPTION:
The TCM receives input on throttle position from either a TPS or a signal transmitted by the engine electronic controls.

Vehicles not equipped with electronically-controlled engines have a TPS attached to the engine fuel control linkage. The TPS continuously sends the exact throttle position to the TCM.

The TPS is a sliding resistor sensor (potentiometer) actuated by a mechanical linkage. The TCM delivers a constant voltage to one terminal of the TPS resistive strip. The other TPS terminal connects to ground. The resistor contacts of the TPS are connected to provide a regulated voltage signal input to the TCM.

When actuated by the mechanical throttle cable, the contacts of the resistor move along the resistive strip. As the contacts slide along the resistive strip, a voltage is sent to the TCM. At each increment of 0.178 mm (0.007 inch) along the resistive strip, the contacts deliver a different voltage to the TCM. The different voltages are interpreted as throttle sensor movement. The TCM converts travel distance (mm) into throttle opening percentage.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC P0123 is stored in the TCM history.
2. The TCM uses the default throttle value, based on engine torque and speed.
3. The TCM forces Variable Modulated Main off.
4. The TCM freezes shift adapts (DNA).
5. The TCM inhibits Torque Converter Clutch (TCC) engagement.
6. The CHECK TRANS light Illuminates (non-OBD II strategy).

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

DIAGNOSTIC AIDS:
DTC P0123 indicates the TCM has detected a voltage signal from the TPS higher than the calibrated supply voltage, that can be caused by the following:
1. A short to battery in W112 or W144 circuits.
2. Analog TPS source set in calibration in non-analog TPS applications.
3. Analog TPS source set by CMC Override Throttle Source using the diagnostic tool in non-analog TPS application.
4. Defective sensor sharing 5V supply shorted to battery.
5. 5V wire shorted to battery in transmission internal harness.
6. Broken or defective connector assemblies allowing pushed back pins to short together.
7. Unlocked connectors, missing seal plugs allowing moisture in connectors.
8. TCM issue.

When diagnosing for an intermittent short or open circuit condition, massage the wiring harness while watching the test equipment for a change.

You may have to drive the vehicle in order to experience a fault.

CIRCUIT DESCRIPTION:
The TCM requires a switched ignition voltage input. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply voltage to wire 163 in the 80-way connector at the TCM. DTC P0561 when the TCM detects large variations in system voltage and variations near the low system voltage threshold. This DTC is only enabled with GM L96 applications.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0561 is active, the following conditions occur:
1. DTC is stored in the TCM history.
2. No response.
3. The TCM forces the Variable Modulated Main off.
4. The TCM freezes shift adapts (DNA).
5. The TCM does not illuminate the CHECK TRANS light.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service Information and therefore should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. Load-testing any transmission-related circuits with any other electrical devices such as vehicle lamps or relays, especially with the TCM connected to the harness. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. You may have to drive the vehicle in order to experience a fault.

5. This DTC indicates a variation in ignition voltage. Common ignition circuit problems for this DTC are a fault in the feed wires to the TCM, a defective ignition switch, or a large vehicle accessory load on the ignition circuit.

6. A vehicle charging system failure may cause this DTC under certain circumstances.

7. This DTC may indicate that an internal voltage problem has occurred inside the TCM. The use of a substitute TCM would be a good way to diagnose this problem.

8. A defective vehicle battery may induce this DTC.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension.
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open circuit condition, massage the wiring harness while watching the test equipment for a change.

CIRCUIT DESCRIPTION:
The TCM requires a switched ignition voltage input to operate. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply voltage to wire 163 in the 80-way connector at the TCM. DTC P0562 is set when the TCM detects low ignition voltage by comparing to a calibration value. This DTC is only enabled with GM L96 applications.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. No response.
3. The TCM forces Variable Modulated Main off.
4. The TCM freezes shift adapts (DNA).
5. The TCM inhibits TCC engagement.
6. DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:/CHECK TRANS LIGHT
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTCs, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. Load-testing any transmission-related circuits with any other electrical devices such as vehicle lamps or relays, especially with the TCM connected to the harness. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. You may have to drive the vehicle in order to experience a fault.

5. This DTC indicates a variation in ignition voltage. Common ignition circuit problems for this DTC are a fault in the feed wires to the TCM, a defective ignition switch, or a large vehicle accessory load on the ignition circuit.

6. A vehicle charging system failure may cause this DTC to set under certain circumstances.

7. Vehicle components such as an ignition switch or TCM ignition relay may cause this DTC to set and not be active, this indicates that an intermittent condition may exist in these components.

8. A defective vehicle battery may induce this DTC to set. Test the vehicle battery to verify proper voltage and load capacity.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension.
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open circuit condition, massage the wiring harness while watching the test equipment for a change.

CIRCUIT DESCRIPTION:
The TCM requires a switched ignition voltage input to operate. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply voltage to wire 163 in the 80-way connector at the TCM. DTC P0563 sets when the TCM detects high ignition voltage by comparing to a calibrated value for calibrated number of samples. This DTC is only enabled with GM L96 applications.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. The TCM forces Variable Modulated Main off.
3. The TCM freezes shift adapts (DNA).
4. The TCM inhibits Torque Converter Clutch (TCC) engagement.
5. DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
The following procedures are not documented in any OEM procedures or in any OEM Troubleshooting or Service information and should not be used as a method to diagnose any transmission DTC’s, function, or shift quality concern:

1. Back-probing any connections used for transmission features or functions may damage and/or unlock terminals from the back-probed connector creating permanent or intermittent shorts and/or open circuits. If possible, use the J-39700 Breakout Box, the appropriate harness adapters, and appropriate magnetic overlays to troubleshoot the vehicle.

2. Load-testing any transmission-related circuits with any other electrical devices such as vehicle lamps or relays, especially with the TCM connected to the harness. Use J-39700 Breakout Box and appropriate harnesses with the diagnostic tool to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting information.

3. Piercing a wire to check for voltages, shorts-to-grounds or other wires anywhere in the circuit but especially at the TCM. This creates a leak path for moisture and damages the wire and insulation.

4. A defective vehicle charging system that is overcharging may cause this DTC.

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
1. A bent terminal.
2. A backed-out terminal.
3. A damaged terminal.
4. Poor terminal tension.
5. A chafed wire.
6. A broken wire inside the insulation.

When diagnosing for an intermittent short or open circuit condition, massage the wiring harness while watching the test equipment for a change.

CIRCUIT DESCRIPTION:
At the power up and after clearing DTCs, the TCM performs a self-test to determine if the calibration in memory is valid.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC P0602 is stored in the TCM history.
2. The TCM does not illuminate the CHECK TRANS light (non-OBD II strategy).
3. The TCM returns to the boot program, and then waits to be recalibrated.
4. Transmission operates in hydraulic default, Reverse, Neutral, and 3rd ranges.
5. DTC is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
TCM must be recalibrated with a valid VEPS calibration.

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) performs an internal memory self-test at power up that tests Flash Memory.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light illuminates.
2. Hydraulic Default. The transmission is restricted to Reverse, Neutral, and 3rd range.

CONDITIONS FOR CLEARING THE DTC:
Replace TCM.

DIAGNOSTIC AIDS:
Replace TCM.

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) performs an internal memory self-test at power up that writes and reads patterns at specific RAM locations to verify that all addresses and data lines are functioning correctly.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light illuminates.
2. DTC is stored in the TCM history on next key cycle.
3. The TCM returns to the boot program.
4. The TCM inhibits shifts to range.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT
Replace TCM.

DIAGNOSTIC AIDS:
Replace TCM.