8

Repair the vehicle wiring harness.

Go to Step 9

Go to Step 10

NOTE: The vehicle OEM has responsibility for
all external wiring. Harness repairs performed
by Allison Transmission distributors and dealers
are not covered under Allison Transmission
warranty.
Is the repair complete?
9

1.
2.

Turn ignition OFF.
Install the J-47278 Breakout Harness to the
transmission 24-way connector. Leave the
OEM harness disconnected.
3. Using a Digital volt/ohmmeter (DVOM),
measure between pins 10 and 14 and
all other pins on the J-39700 Universal
Breakout Box and J-47278-1 Transmission
24-way Magnetic Overlay and chassis
ground.
Continuity would indicate a wire to wire in
the internal transmission harness wires. Was
continuity observed?

Go to Step 12

Go to Step 10

10

1.
2.

Go to Step 12

Go to Step 11

Turn ignition OFF.
Install the J-47278 Breakout Harness to the
transmission 24-way connector. Leave the
OEM harness disconnected.
3. Using a Digital volt/ohmmeter (DVOM), test
for short to ground between pins 10 and
14 on the J-39700 Universal Breakout Box
and the J-47278-1 Transmission 24-way
Magnetic Overlay and chassis ground.
Continuity would indicate a short to ground in
the internal transmission harness wires, Was
continuity observed?

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 56 of 72

DTC P2762 TCC (PCS) Control Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No

Turn ignition OFF.
Remove transmission oil pan (refer to
the Service Manual or the In-Chassis
Maintenance).
3. Disconnect the internal transmission wire
harness connectors on the TCC solenoid.
4. Using a Digital Volt/Ohmmeter (DVOM),
test measure the TCC solenoid resistance
between pins A and B.
Is the resistance within specified values?

Refer to Table 6-8

Go to Step 14

Go to Step 13

11

1.
2.

12

Replace the internal transmission wire harness
(refer to the Service Manual or the In-Chassis
Maintenance).

Go to Step 17

13

Replace the TCC solenoid (refer to the Service
Manual or the In-Chassis Maintenance).

Go to Step 17

14

NOTE: In most cases the TCM is not at fault.
Investigate thoroughly before replacing the
TCM. Refer to 4-6. TCM Diagnostic Procedure.

Go to Step 17

15

1.

If the service outlet is authorized to use
the TCM Reflash software, recalibrate the
original TCM with the latest calibration and
software.
2. Once the TCM recalibration is complete,
use the Allison DOC® software to check for
active DTCs.
Is DTC P2762 active after reprogramming the
TCM?

Go to Step 16

16

1.
2.

Go to Step 17

3.
4.

5.

6.

Turn ignition OFF.
Install a test TCM and torque bolt in the
TCM to 2.0-3.2 N·m (18-28 lb in).
Start the engine and apply and release
service brakes.
Using the Allison DOC® software check for
active codes and monitor the TCC status
on the TCM input wire 178.
If codes are not active with the test TCM
installed, then turn ignition OFF and
re-install the original TCM.
Restart engine and check again for active
DTCs.

NOTE: In most cases, the TCM is not at
fault. Investigate thoroughly before replacing
the TCM. Refer to 4-6 TCM DIAGNOSTIC
PROCEDURE.
Is repair or replacement complete?

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

Go to Step 17

SIL 14-TR-18
September, 2018
Page 57 of 72

DTC P2762 TCC (PCS) Control Circuit—Performance (cont'd)
Step

Action

17

To verify the repair:
1. Clear the DTC.
2. Drive the vehicle under conditions shown in
failure records.
Did DTC P2762 return?

Value(s)

Yes

No

Begin the
diagnosis again.
Go to Step 1

Repair complete.

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 58 of 72

Appendix B. 3K4K Troubleshooting

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 59 of 72

DTC P0600 Internal Serial Peripheral Interface (SPI) Diagnostics
Circuit Description
This DTC is set when the TCM detects an internal communication fault between the microprocessor and the
solenoid control integrated circuits internal to the TCM.
Actions Taken When the DTC Sets
When DTC P0600 is active, the following conditions occur:
• The MALFUNCTION INDICATOR LAMP illuminates on first occurrence.
• The DTC is stored in the TCM history.
• Transmission operates in hydraulic default: R (Reverse), N (Neutral), and 3 (Third Range).
Conditions for Clearing the DTC
Replace the TCM.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
1. This step tests for an active DTC.
2. Validate the DTC.
3. Replace the TCM.
Step

Action
DOC®

Value(s)

Yes

No

1

Connect the Allison
software.
Start engine.
Using the Allison DOC® software, record
snapshot showing active or inactive DTC(s).
4. Review failure records report from snapshot
to determine conditions when DTC occurs.
Is DTC P0600 active?

Go to Step 3

Troubleshoot
any other active
DTCs if present.
If no other DTCs
are active, go
to Step 2

2

1.
2.
3.

Go to Step 3

System OK.
Clear inactive
DTCs and return
vehicle to service

1.
2.
3.

Clear the DTC.
Start the engine and test drive the vehicle.
Attempt to duplicate the same conditions
observed in the failure records (range
attained, temperature, etc.).

NOTE: This DTC is intended to detect an
internal TCM failure.
Did DTC P0600 return?

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 60 of 72

DTC P0600 Internal Serial Peripheral Interface (SPI) Diagnostics (cont'd)
Step
3

Action
1.
2.

Turn ignition OFF.
Install a new TCM and tighten the bolt to
2.0 – 3.2 N·m (18-28 lb in).
3. Install or reconnect OEM components and
connectors.
4. Start engine.
5. Using the Allison DOC® software, check for
active DTCs.
Is DTC P0600 active with the new TCM?

Value(s)

Yes

No

Begin the
diagnosis again.
Go to Step 1

Repair complete.

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 61 of 72

DTC P07CE Neutral At Stop Not Functioning
Description:
This DTC is set when the Neutral At Stop (NAS) is not functioning. This test monitors the inputs that affect the NAS
functionality. This DTC is enabled when the Neutral At Stop: Emissions Credit Vehicle is enabled.
How to Determine “NEUTRAL At Stop: Emission Credit Vehicle” Calibration Setting in the TCM:
The setting for “NEUTRAL At Stop: Emission Credit Vehicle” can be found using Allison DOC® Premium version
2018.1 or later by choosing “Additional Calibration Information” on the Calibration Information screen.

Figure 1. Calibration Information Screen
The setting for “NEUTRAL At Stop: Emission Credit Vehicle” can also be found in the FuelSense® section
of Allison Calibration Configuration Tool (ACCT), which can be found in the Engineering section of the
http://hub.allisontransmission.com/. The ACCT Calibration Summary Report will display this new parameter and
calibration setting only if the answer is set to YES in the calibration.

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 62 of 72

DTC P07CE Neutral At Stop Not Functioning (cont'd)

When viewing or editing service calibration requests in ACCT, a green leaf icon
will appear next to the
“NEUTRAL At Stop: Emission Credit Vehicle” and “NEUTRAL AT STOP” parameters if the answer to “NEUTRAL At
Stop: Emission Credit Vehicle” parameter is set to YES. In this case, these parameters can only be modified by
Allison service personnel upon receipt of OEM authorization.
Action Taken When the DTC Sets
When DTC P07CE is active, the following conditions occur:
• The CHECK TRANS indicator is illuminated.
• The DTC is stored in the TCM history.
• TCM inhibits Neutral at Stop operation.
Conditions for Clearing the DTC/CHECK TRANS Light
Use Allison DOC® Premium to clear the DTC from TCM history. The TCM automatically clears the DTC from TCM
history if the vehicle completes 40 warm-up cycles without the DTC recurring.
Diagnostic Aids
Setting one or more of the following conditions will cause NAS not to function and DTC P07CE to set:
• The Service Brake Input has failed setting DTC(s)
• U0400 Invalid Communication Link Data Received
• P0703 Brake Switch Circuit
• Engine Speed
• P0725 Engine Speed Sensor Circuit
• P0726 Engine Speed Sensor Circuit - Performance
• P0727 Engine Speed Sensor Circuit - No Signal
• NAS input fails
• When NAS is configured as a wired input, will set a P071A in addition to the P07CE
• Transmission Sump Temperature
• P0711 Transmission Fluid Temperature Sensor Circuit – Performance
• P0712 Transmission Fluid Temperature Sensor Circuit – Low Input
Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 63 of 72

DTC P07CE Neutral At Stop Not Functioning (cont'd)
• P0713 Transmission Fluid Temperature Sensor Circuit – High Input
• Throttle Input failed when input is over the CAN bus
• Verify throttle signal is present on the Data Bus using the Data Bus Viewer
• Throttle Input failed when input is an analog signal or a Pulse Width Modulation (PWM) signal
• P0122 Pedal Positon Sensor Circuit – Low Voltage
• P0123 Pedal Positon Sensor Circuit – High Voltage
• P1891 Throttle Position Sensor (TPS) PWM Signal – Low Input
• P1892 Throttle Position Sensor (TPS) PWM Signal – High Input
Test Description
Each item number description in this list correlates to the identical number shown in the DTC table "Step" column
and is meant to briefly describe the "Action" column procedures for a particular step in the table. The DTC
troubleshooting step descriptions examine the following:
1. Check for active DTC.
2. Check for NAS not functioning.
3. Recalibrate TCM with updated version of original calibration.
4. Install a test TCM.
Step

Action
Connect the Allison DOC® software.
Start engine.
Record snapshot using the Allison DOC®
software showing active or inactive code(s).
4. Review the failure records report from
snapshot to determine conditions when the
DTC occurs.
Is DTC P07CE active?

1

1.
2.
3.

2

1.
2.

Clear the DTC.
Start the engine and test drive the vehicle.

Value(s)

Yes

No

Troubleshoot
any other active
DTCs, if present.
If no other DTCs
are active, go
to Step 5

Go to Step 2

Go to Step 4

System OK.
Clear inactive
DTCs and
return vehicle
to service.

NOTE: This DTC is intended to detect NAS not
functioning due to a failed input.
3.

Attempt to duplicate the same conditions
observed in the failure records (range
attained, temperature, etc.).
Did DTC P07CE return?

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 64 of 72

DTC P07CE Neutral At Stop Not Functioning (cont'd)
Step

Action

Value(s)

Yes

No

3

1.

Go to Step 4

Go to Step 5

4

1.
2.

Turn ignition OFF.
Install a test TCM and tighten the bolt to
2.0–3.2 N·m (8-28 lb in).
3. Install or reconnect OEM components and
connectors.
4. Start engine.
5. Using the Allison DOC® software, check for
active DTCs.
6. If DTC are not active with a test TCM
installed, then turn ignition off and reinstall
the original TCM.
7. Restart engine and check again for active
DTCs.
Is DTC P07CE active with original TCM and
inactive with test TCM?

Install a new
TCM. Go to
Step 5 after
repairs are made.

If DTC is active
with both the test
TCM and the
original TCM, do
not replace the
TCM. Review
Diagnostic Aids
for this DTC.
Begin diagnosis
again. Go to
Step 1

5

Acquire new Allison DOC® snapshot while
driving vehicle under same conditions, if
possible, noted in failure records from Step 1.
Did DTC P07CE return?

Begin the
diagnosis again.
Go to Step 1

Repair complete.

If the service outlet is authorized to use
the TCM Reflash software, recalibrate the
original TCM with the latest calibration and
software.
2. Once the TCM recalibration is complete,
use Allison DOC® to check for active DTCs.
Is DTC P07CE active after reprogramming the
TCM?

Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 65 of 72

DTC P0703 Brake Switch Circuit

Circuit Description
This test monitors whether vehicle service brake switch status is in a stuck "ON" or "OFF" state.
Service brake status is relayed to the TCM by a mechanical switch, or over the J1939 datalink indicating the
service brake has been applied. Input wire 162 is used to send a positive signal to the TCM. Wire 103 is used in
this circuit as the signal return to the TCM.
DTC P0703 is only triggered when input wire 162 is being used for the service brake status signal and when the
number of vehicle accelerations with brake switch “ON” exceeds a calibration value. This DTC may also set when
the number of vehicle decelerations to a stop with the brake switch “OFF” exceeds a calibration value. This code
will not be triggered if the Service Brake Status Input is broadcast on J1939 datalink.