at the TCM.
3. Leave the connector disconnected.
4. On the J-47275-1 TCM Magnetic Overlay
on the J-39700 Universal Breakout Box,
measure pins 62 and 3 to chassis ground.
Was continuity measured between these pins?

Go to Step 8

Go to Step 13

8

Repair the vehicle wiring harness.

Go to Step 11

Go to Step 13

Go to Step 13

Go to Step 11

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

Repair or replace the brake pressure switch
assembly.
Is the repair complete?

10

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

11

If the service outlet is authorized to use the
TCM Reflash software, recalibrate the original
TCM with the latest calibration and software.
Is DTC P071A active after reprogramming the
TCM?

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

SIL 14-TR-18
September, 2018
Page 22 of 72

DTC P0703 Brake Switch Circuit (cont'd)
Step
12

Action
1.
2.
3.
4.

5.

6.

Turn ignition OFF.
Install test a TCM and torque bolt in the
TCM to 2.0-3.2 N·m (18-28 lb in).
Start engine and apply and release service
brakes.
Using the Allison DOC® software check for
active codes and monitor service brake
status on TCM input wire 162.
If codes are not active with test TCM
installed, then turn the ignition OFF and
re-install the original TCM.
Restart engine and check again for active
DTCs.

Value(s)

Yes

No

Go to Step 13

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?
13

To verify the repair:
1. Clear the DTC.
2. Using the Allison DOC® software, monitor
the status of input wire 162 while applying
and releasing the service brake.
3. Drive the vehicle under normal operating
conditions.
Did the DTC P0703 return?

Begin the
diagnosis again.
Go to Step 1

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

Repair complete.

SIL 14-TR-18
September, 2018
Page 23 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance

Circuit Description
PCS2 is a Pressure Proportional to Current (PPC) solenoid used to control oncoming and off-going and holding
pressure to any one of five clutches.
The TCM sends control current to PCS2 from High Side Driver 2 (HSD2) via wire 171. HSD2 is continuously on
unless the TCM detects a fault condition. The TCM regulates the amount of current to PCS2 by switching the
low side driver ON and OFF. Wire 136 completes the circuit between PCS2 and its low side driver. DTC P0965
indicates that the TCM processor has detected an open, short to ground, short to power or wire to wire shorts
condition in the electrical circuit.
Actions Taken When the DTC Sets
When DTC P0965 is active, the following conditions occur:
• If the failure occurs while in a forward range, a shift to 1st, 3rd, or 5th range is made.
• While diagnostic response is active, if shift selector is moved to N (Neutral), transmission shifts to neutral;
if the shift selector is moved to R (Reverse), transmission shifts to reverse. If the shift selector is moved
to D (Drive) range or R (Reverse) and transmission is compromised by overspeeding or direction change,
transmission shifts to neutral.

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

SIL 14-TR-18
September, 2018
Page 24 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
• The Service Transmission message is displayed in the vehicle message center on the Silverado 4500HD,
5500HD, 6500 HD and the Navistar CV models.
• The Malfunction Indicator Lamp (MIL) illuminates on first occurrence.
• The DTC is stored in the TCM history.
NOTE: When connecting the Allison DOC® software to a General Motors Silverado 4500HD, 5500HD and
6500HD models or a NAVISTAR CV model use the J-48624 Translator and the J-41788 OBD II Connector.
Conditions for Clearing the DTC
Use the Allison DOC® software 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 Allison procedures or in any Allison Troubleshooting
Manual or Service Manual and should not be used as a method to diagnose any transmission DTCs, function,
or shift quality concern:
– 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 Allison DOC® software, J-48624 Translator and J-41788 OBD II Connector, and J 47275-1
TCM Overlay and J 39700 Universal Breakout Box to troubleshoot the vehicle.
– 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 GM diagnostic tools with Tech 2 Pro Optima
to monitor the circuit performance in question unless otherwise specified in the various Troubleshooting
Manuals.
– 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.
An intermittent circuit condition can allow this DTC to set. Make sure you check for the following conditions at the
OEM harness first, then at the transmission internal harness:
• DTC P0965 indicates an open, short to ground, short to power or wire to wire shorts in the electrical circuit
for PCS2.
• Inspect the wiring for poor electrical connections at the TCM and the transmission main connector. Look for
the following conditions:
– A bent terminal
– A backed-out terminal
– A damaged terminal
– Poor terminal tension
– A chafed wire
– A broken wire inside the insulation

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

SIL 14-TR-18
September, 2018
Page 25 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
• Inspect OEM wiring harness routing. Look for possible contact points where chafing could occur leading to
an open circuit condition. Moving parts on the vehicle could be contacting the harness; this includes parking
brake drum, suspension components, transmission shift linkage, etc.
• When diagnosing for an intermittent short or open, massage the wiring harness while watching the test
equipment for a change. It may be necessary to check continuity at individual wires within a harness to
isolate an intermittent open condition.
• You may have to drive the vehicle in order to experience a fault. Use the data obtained from failure records to
determine transmission range and/or certain vehicle operating variables such as temperature, run time, etc.
This data can be useful in reproducing the failure mode when the DTC was set.
Tool Requirements:
• Allison DOC® software
• J-39700 Universal Breakout Box
• J-47275 TCM Breakout Harness
• J-47275-1 TCM Magnetic Overlay
• J-47278-1 Transmission Magnetic Overlay
• J-46708 Digital Multimeter
Test Description
The numbers below refer to the step numbers on the diagnostic table.
1. Beginning the Troubleshooting Process.
2. This step tests for the proper ignition voltage.
3. Verification of DTC after clearing the DTC from the TCM.
4. This step tests the OEM harness for an open condition in either wire 136 or wire 171 of the OEM
chassis harness.
5. This step tests the OEM harness for a wire to wire shorts condition in either wire 136 or wire 171 of the
OEM chassis harness.
6. This step tests the OEM harness for a short to ground condition in either wire 136 or wire 171 of the
OEM chassis harness.
7. This step tests the OEM harness for a short to power condition in either wire 136 or wire 171 of the
OEM chassis harness.
8. Repair of the OEM chassis wiring harness.
9. This step tests for wire to wire shorts in the transmission internal wire harness.
10. This step tests for short to ground in the transmission internal wire harness.
11. This step checks the resistance of the PCS2.
15. Recalibrate the TCM with updated version of original calibration.
16. Install a test TCM.

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

SIL 14-TR-18
September, 2018
Page 26 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
NOTE: The J-39700 Universal Breakout Box, adapter harnesses, jumpers, and the J-46708
Digital Multimeter leads add a few ohms of resistance to a circuit. Refer to BEGINNING THE
TROUBLESHOOTING PROCESS for the procedure to determine the tool resistance that is added to a
test circuit.

NOTE: The Allison Transmission warranty, or the extended coverage for parts and labor, does not cover
the repair or replacement of OEM or bodybuilder-provided components or any external wire harnesses not
provided by Allison Transmission, Inc.
Before repairing or replacing these components or circuits that caused a transmission issue, always
contact the vehicle OEM call center and/or the vehicle OEM or bodybuilder service representative to
verify the warranty coverage and proper payment arrangements, arrange an alternate sublet or repair
plan (if needed), and get troubleshooting assistance for the repair (such as vehicle schematics, DTC
trees, parts assistance, etc.).

Step

Action

1

Was BEGINNING THE TROUBLESHOOTING
PROCESS - 5th Gen 1k2k performed?

2

1. Connect the Allison DOC® software.
2. Start the engine.
3. Record the DTC failure record data.
4. Monitor ignition voltage.
Is the voltage within the specified values?

3

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.).

Value(s)

9–18V

Yes

No

Go to Step 2

Go to
BEGINNING
THE TROUBLE
SHOOTING
PROCESS - 5th
Gen 1k2k

Go to Step 3

Resolve voltage
problem. (Refer
to P0562 and
P0563)

Go to Step 4

Go to Diagnostic
Aids

NOTE: This DTC is intended to detect an open,
short to ground, short to power or wire to wire
shorts condition in the PCS2 electrical circuit.
Did DTC P0965 return?

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

SIL 14-TR-18
September, 2018
Page 27 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No

4

1.
2.

Turn ignition OFF.
Install the J-47275 TCM Breakout Harness
Adapter, J-47275-1 TCM Magnetic Overlay
and J-39700 Universal Breakout Box on
the TCM 80-way vehicle wiring harness
connector. Leave TCM disconnected.
3. Remove 24-way connector from the
transmission. At the 24-way transmission
harness connector install a jumper wire
from pin 16 and 17, leave transmission
disconnected.
4. At the TCM Breakout Box, measure pins
36 and 71 on the J-47275-1 TCM Magnetic
Overlay for continuity.
Did the pins have continuity between them?

Go to Step 8

Go to Step 5

5

1.
2.
3.

Turn ignition OFF.
Disconnect the TCM 80-way connector.
Install the OEM side 80-way connector
to the Breakout Box. Leave the TCM
disconnected.
4. Remove the jumper wire and leave
the 24-way transmission connector
disconnected.
5. On the J-39700 Universal Breakout Box,
measure pins 36 and 71 to all other pins on
the J-47275-1 TCM Magnetic Overlay.
Wire to wire continuity indicates a short between
OEM chassis wiring harness wires. Was
continuity measured?

Go to Step 8

Go to Step 6

6

1.
2.

Go to Step 8

Go to Step 7

Turn ignition OFF.
Install the J-47275 TCM Breakout Harness
Adapter, J-47275-1 TCM Magnetic Overlay
and J-39700 Universal Breakout Box on
the TCM 80-way vehicle wiring harness
connector. Leave TCM disconnected.
3. Disconnect the 24-way transmission
connector.
4. On the J-39700 Universal Breakout Box,
measure pins 36 and 71 to chassis ground
on the J-47275-1 TCM Magnetic Overlay.
Was continuity measured between these pins
and to chassis ground?

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

SIL 14-TR-18
September, 2018
Page 28 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No

7

1.
2.

Turn ignition OFF.
Install the J-47275 TCM Breakout Harness
Adapter, J-47275-1 TCM Magnetic Overlay
and J-39700 Universal Breakout Box on
the TCM 80-way vehicle wiring harness
connector. Leave TCM disconnected.
3. Remove 24-way connector from the
transmission.
4. Turn ignition ON.
5. On the J-39700 Universal Breakout Box,
measure pins 36 and 71 to all other pins on
the J-47275-1 TCM Magnetic Overlay.
Voltage on either pins indicate a short to power
in the OEM chassis wiring harness. Was voltage
measured?

Go to Step 8

Go to Step 9

8

Repair the vehicle wiring harness.

Go to Step 17

Go to Step 9

Go to Step 12

Step 10

NOTE: The vehicle OEM has responsibility
for all external wiring. 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/ohmeter (DVOM),
measure between pins 16 and 17 and
all other pins on the J-39700 Universal
Breakout Box and J-47278-1 Transmission
24-way Magnetic Overlay.
Continuity would indicate a wire to wire in
the internal transmission harness wires. Was
continuity observed?

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

SIL 14-TR-18
September, 2018
Page 29 of 72

DTC P0965 Pressure Control Solenoid 2 (PCS2) Control
Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No

Go to Step 12

Go to Step 11

Go to Step 12

10

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/ohmeter (DVOM),
measure between chassis ground pins 16
and 17 on the J-39700 Universal Breakout
Box and the 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?

11

1.
2.

Turn ignition off.
Remove the transmission oil pan (refer
to the Service Manual or the In-Chassis
Maintenance).
3. Disconnect the internal transmission wire
harness connectors on the PCS2.
4. Using a Digital Volt/Ohmeter (DVOM), test
measure the PCS2 resistance between
pins A and B.
Is the resistance within specified values?

Refer to Table 6-8

Go to Step 13

12

1.

Refer to Table 6-8

Go to Step 17

13

1.

Replace PCS2 (refer to Service Manual or
the In-Chassis Maintenance).
Is the replacement complete?

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