Allison

Allison 1000 & 2000 Gen 4 Fault Codes: P0123 Pedal Position Sensor Circuit High Voltage

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) receives input on throttle position from either a Throttle Position Sensor (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 transmission 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.

CONDITIONS FOR RUNNING THE DTC:
1. The components are powered, and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).
2. DTC P0122 Throttle/Pedal Position Sensor/Switch A Circuit Low Input is not active.

CONDITIONS FOR SETTING THE DTC:
DTC P0123 sets when the TCM detects a throttle position sensor voltage greater than 4.75 for 5 seconds.

ACTION TAKEN WHEN DTC SETS:
1. DTC P0123 is stored in the TCM history.
2. The TCM uses the default throttle value.
3. The TCM freezes shift adapts (DNA).
4. The TCM inhibits TCC engagement.
5. The CHECK TRANS light is illuminated.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool may be used to clear the code 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:
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, 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.

Allison 1000 & 2000 Gen 4 Fault Codes: P0218 Transmission Fluid Over Temperature Condition

CIRCUIT DESCRIPTION:
The flow of transmission fluid starts in the transmission pan. Fluid is then drawn through the filter and internal passages into the oil pump assembly. The oil pump pressurizes the fluid into main-pressure that is regulated at the main-pressure regulator valve. From this point, fluid is directed to the F trim solenoid and to the control-main regulator and control-main relief valve into the control-main filter assembly and on to all solenoids for use as control pressure. Hot fluid leaving the torque converter is routed through the converter flow valve to cooler lines and into the cooler assembly. The transmission oil cooler is located in the radiator. The vehicle may be equipped with an auxiliary oil cooler. The cooled fluid is returned to the transmission through the return cooler line and to the transmission lube circuit. The automatic transmission fluid temperature (TFT) sensor, which is part of the PSM, is located in the oil pan.

If the Transmission Control Module (TCM) detects a high TFT for an extended period of time, then DTC P0218 sets.

CONDITIONS FOR RUNNING THE DTC:
1. DTCs P0711, P0712, P0713 are not active.
2. The components are powered, and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).
3. Engine speed is greater than 200 rpm for more than 5 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC P0218 sets when the TCM detects a transmission sump temperature greater than 126°C (252°F) for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS:
1. The TCM does not illuminate the CHECK TRANS light.
2. The TCM freezes shift adapts (DNA).
3. The TCM records the operating conditions when the CONDITIONS FOR SETTING THE DTC: are met. The TCM stores this information as Failure Records.
4. DTC P0218 is stored in the TCM history.
5. The TCM defaults to “hot mode” shift schedule where 4th-range is held and TCC is inhibited to increase engine speed and improve cooler flow.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
1. A Scan Tool may be used to clear the code from the TCM history.
2. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.
3. The TCM cancels the DTC default actions when the fault no longer exists, and the DTC passes test.

DIAGNOSTIC AIDS:
1. Verify the customer’s driving habits, such as trailer towing, etc.
2. The Scan Tool transmission fluid temperature (TFT) should rise steadily during warm-up cycles and then stabilize.
3. DTC P0218 may set after DTC P0711 (not active) has set. Follow the diagnostic information for DTC P0711 before proceeding to the diagnostic for DTC P0218. Repairing the condition that set DTC P0711 will likely eliminate DTC P0218.

Allison 1000 & 2000 Gen 4 Fault Codes: P0561 Unrealistic Variations in Vehicle System Voltage

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) requires a switched ignition voltage input and a direct battery voltage input. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply voltage to pins 102 and 104 in the J1 connector at the TCM. Battery direct voltage is supplied to pin 103 at the J1 connector.

CONDITIONS FOR RUNNING THE DTC:
1. The test becomes enabled when the engine has been running above 400 rpm for at least 0.5 seconds.
2. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).

CONDITIONS FOR SETTING THE DTC:
P0561 sets when the TCM detects a large variation in ignition voltage or battery direct voltage. When an ignition or battery direct voltage variation of 4.0V or greater is detected for 0.5 seconds, a fault pending is reported. After 1.0 second of 4.0V or greater variation, a DTC is set with a failure response.

ACTION TAKEN WHEN THE DTC SETS:
When DTC P0561 is active, the following conditions will occur:
1. DTC P0561 is stored in the TCM history.
2. Hydraulic default is commanded. Shift selector position and hydraulic state of logic valves determine the range attained.
3. The CHECK TRANS light illuminates.
4. The TCM inhibits TCC engagement.
5. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool may be used to clear the code 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:
1. You may have to drive the vehicle in order to experience a fault.
2. This DTC indicates a variation in ignition voltage or battery direct 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. Battery direct voltage problems may be due to loose or corroded battery cables, a bad connection at the battery direct feed terminal (103), or an internal TCM failure due to a burnt trace.
3. A vehicle charging system failure may cause this DTC under certain circumstances.
4. This code 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.
5. 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, massage the wiring harness while watching the test equipment for a change.

Allison 1000 & 2000 Gen 4 Fault Codes: P0562 System Voltage Low

CIRCUIT DESCRIPTION:
The Transmission Control Module (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 pins 102 and 104 in the J1 connector at the TCM.

CONDITIONS FOR RUNNING THE DTC:
1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).
2. The engine speed is greater than 450 rpm for 10 seconds.

CONDITIONS FOR SETTING THE DTC:
DTC P0562 sets when the TCM detects the following condition:
12 volt TCM – Ignition voltage is detected below 8V at 0°C (32°F) for a total of 5 out of 7 seconds. The voltage threshold is temperature dependent varying from 5V at -60°C (-75°F) to 9V at 20°C (68°F).

24 volt TCM – Ignition voltage is detected below 17V at 0°C (32°F) for a total of 5 out of 7 seconds. The voltage threshold is temperature dependent varying from 14V at -60°C (-75°F) to 18V at 20°C (68°F).

ACTION TAKEN WHEN THE DTC SETS:
1. If the DTC is active while vehicle is in a forward range, transmission shifts to neutral, 1st, 3rd, or 5th range.
2. If the DTC is active while in reverse or neutral, transmission shifts to neutral.
3. If the shift selector is moved to forward range, transmission shifts to neutral, 1st, 3rd, or 5th range.
4. If the shift selector is moved to reverse or neutral, transmission shifts to neutral. Diagnostic response honors the inhibit latched at the time the DTC is set. If a latched inhibit is present and PRNDL is incorrect, transmission shifts to neutral range. If PRNDL is correct, GPI request is responded to.
5. The CHECK TRANS light is illuminated.
6. The TCM inhibits TCC engagement.
7. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool may be used to clear the code 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:
1. A defective vehicle battery may allow this DTC to set. Test the vehicle battery to verify proper voltage and load capacity.
2. A defective vehicle charging system may cause this DTC.
3. 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.

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, massage the wiring harness while watching the test equipment for a change.

Allison 1000 & 2000 Gen 4 Fault Codes: P0563 System Voltage High

CIRCUIT DESCRIPTION:
The Transmission Control Module (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 pins 102 and 104 in the J1 connector at the TCM.

CONDITIONS FOR RUNNING THE DTC:
1. The engine speed is greater than 450 rpm for one second.
2. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).

CONDITIONS FOR SETTING THE DTC:
DTC P0563 sets when the TCM detects the following condition:
12 volt TCM – Ignition voltage is above 18V for 6 out of 10 seconds.
24 volt TCM – Ignition voltage is above 32V for 6 out of 10 seconds.

ACTION TAKEN WHEN THE DTC SETS:
1. If the DTC is active while the vehicle is in a forward range, the transmission shifts to neutral, 1st, 3rd, or 5th range.
2. If the DTC is active while in reverse or neutral, the transmission shifts to neutral.
3. If the shift selector is moved to a forward range, the transmission shifts to neutral, 1st, 3rd, or 5th range. If the shift selector is moved to reverse or neutral, the transmission shifts to neutral. Diagnostic response honors the inhibit latched at the time the DTC is set. If a latched inhibit is present and PRNDL is incorrect, the transmission shifts to neutral range. If PRNDL is correct, the GPI request is responded to.
4. The CHECK TRANS light is illuminated.
5. The TCM inhibits TCC engagement.
6. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool may be used to clear the code 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:
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, massage the wiring harness while watching the test equipment for a change.

Allison 1000 & 2000 Gen 4 Fault Codes: P0602 TCM Not Programmed

CIRCUIT DESCRIPTION:
At the power up and after clearing codes, the Transmission Control Module (TCM) performs a self-test to determine if the calibration in memory is valid.

CONDITIONS FOR RUNNING THE DTC:
1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).
2. This test will run before any TCM functions.

CONDITIONS FOR SETTING THE DTC:
DTC P0602 sets if the TCM determines the present calibration is invalid.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC P0602 is stored in the TCM history.
2. The CHECK TRANS light illuminates.
3. The TCM returns to the boot program, and then waits to be recalibrated.
4. The TCM inhibits TCC engagement.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
TCM must be recalibrated.

DIAGNOSTIC AIDS:
None

Allison 1000 & 2000 Gen 4 Fault Codes: P0606 Controller Internal Performance – Not Enabled for Pickups or Med Duty “04”

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) completes numerous scheduled tasks during normal operation. If one of the scheduled tasks fails to complete within a specific time limit the TCM will re-attempt this task.

NOTE: The presence of DTC P0606 indicates a TCM software error has occurred and the OEM Transmission Service Department should be contacted.

CONDITIONS FOR RUNNING THE DTC:
The components are powered and ignition voltage is greater than 9V and less than 18V for a 12V TCM, or greater than 18V and less than 32V for a 24 V TCM.

This test is run during the entire ignition cycle.

CONDITIONS FOR SETTING THE DTC:
DTC P0606 sets if a task fails to complete after two consecutive attempts.

ACTION TAKEN WHEN THE DTC SETS:
1. When DTC P0606 is active, the transmission will lock in N (Neutral).
2. DTC P0606 is stored in the TCM history.
3. The CHECK TRANS light illuminates.
4. The TCM freezes shift adapts (DNA).
5. The TCM inhibits TCC engagement.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool can clear the code 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:
None

Allison 1000 & 2000 Gen 4 Fault Codes: P0614 Torque Control Data Mismatch – ECM/TCM

CIRCUIT DESCRIPTION:
Shift Energy Management (SEM) allows the Transmission Control Module (TCM) to request torque reduction from the engine controller. By reducing torque, shifts can be made quicker, at a more consistent output torque which reduces clutch temperatures and increases clutch life. When an engine torque rating exceeds 580 lb ft, Lower Range Torque Protection (LRTP) is used. This feature limits engine torque in lower ranges to protect the transmission from damage if a stall condition occurs.

CONDITIONS FOR RUNNING THE DTC:
1. No DTC U2105 CAN bus error.
2. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).
3. Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
4. This test runs for 30 seconds for the first 20 engine starts after the engine is detected on the J1939 CAN.
5. Engine must be identified by the TCM as an approved make and model.
6. Engine’s torque configuration message (peak torque) must be greater than allowed without SEM (above 580 lb ft gross input torque).

NOTE: Unapproved engines or low torque engines will operate without setting a P0614.

CONDITIONS FOR SETTING THE DTC:
P0614 sets when the TCM detects one of the following conditions:
1. TCM detects a valid engine having the proper torque rating but ECM software is not supporting all the messaging necessary for SEM.
2. TCM detects a valid engine having a torque rating exceeding 580 lb ft that does not support Lower Range Torque Protection (LRTP) messaging.

NOTE: Valid engines with a torque rating exceeding 580 lb ft must have software that is compatible with LRTP or a P0614 is set.

ACTION TAKEN WHEN THE DTC SETS:
1. DTC P0614 is stored in the TCM history.
2. The CHECK TRANS light illuminates.
3. If the TCM and engine ECM software are not compatible, the transmission will be restricted to reverse, neutral, first range, or third range.
4. The TCM inhibits TCC engagement.
5. The TCM freezes shift adapts (DNA).

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool may be used to clear the code 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:
None

Allison 1000 & 2000 Gen 4 Fault Codes: P0701 Transmission Control System Performance

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) monitors the status of the pressure switches at start-up to detect the presence of hydraulic pressure.

CONDITIONS FOR RUNNING THE DTC:
1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM).
2. Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.
3. This test is run after engine start-up and runs as part of the transmission hydraulic initialization.

CONDITIONS FOR SETTING THE DTC:
DTC P0701 sets when transmission fluid temperature is above -25°C (-13°F) with an engine speed above 500 rpm for 6 seconds or 400 rpm for 15 seconds and forward or reverse range is selected and all the pressure switches do not indicate pressure.

ACTION TAKEN WHEN THE DTC
1. DTC P0701 is stored in the TCM history.
2. The TCM inhibits TCC engagement.

CONDITIONS FOR CLEARING THE MIL/DTC
A Scan Tool may be used to clear the code 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:
1. DTC P0701 may be logged if a forward or reverse range is selected immediately after the engine is started and before the TCM detects pressure at the switches (2 to 6 seconds after engine start).
2. A plugged control main filter may cause this code to set. The control main filter is to be changed after the first 8000 km (5,000 miles). Failure to change the filter at this interval may cause this code and other pressure switch codes to set.
3. A cracked internal suction filter tube or damaged tube seal may cause this DTC to set.
4. A stuck lube regulator valve (located in the front support) may cause this DTC to set. A high static oil level with the vehicle running is often a good indication of this complaint. Often pressure switch DTCs are set in this scenario.
5. You may have to drive the vehicle in order to experience a fault.