Was continuity measured between these pins
and chassis ground?

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

SIL 14-TR-18
September, 2018
Page 47 of 72

DTC P2728 Pressure Control Solenoid 1 (PCS1) Control
Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No
Go to Step 9

7

1.
2.

Turn ignition OFF.
Install the J-47275 TCM Breakout Harness
Adapter and the J-39700 Universal
Breakout Box on the 80-way OEM
connector. Leave TCM disconnected.
3. Remove the 24-way connector from the
transmission.
4. Turn ignition ON.
5. Using a DVOM, measure for voltage
between pins 11 and 55 on the 80-way
connector.
Voltage on either pins indicates a short to power
in the wire harness. Was voltage measured?

Go to Step 8

8

Repair the OEM chassis wiring harness.

Go to Step 17

NOTE: The vehicle OEM has responsibility for
all external wiring. OEM chassis wire 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 14 and 15 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

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

Go to Step 10

SIL 14-TR-18
September, 2018
Page 48 of 72

DTC P2728 Pressure Control Solenoid 1 (PCS1) Control
Circuit—Performance (cont'd)
Step

Action

Value(s)

Yes

No

Go to Step 12

Go to Step 11

Go to Step 14

Go to Step 13

10

1.
2.

11

1.
2.

Turn ignition OFF.
Remove the transmission oil pan (refer
to the Service Manual or the In-Chassis
Maintenance).
3. Disconnect internal transmission wire
harness connectors on the PCS1 solenoid
4. Using a Digital Volt/Ohmmeter (DVOM),
test measure thePCS1 solenoid resistance
between pins A and B.
Is the resistance within specified values?

12

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

Go to Step 17

13

Replace the PCS1 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.

Go to Step 16

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 14 and
15 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?

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 P2728 active after reprogramming the
TCM?

Refer to Table 6-8

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

SIL 14-TR-18
September, 2018
Page 49 of 72

DTC P2728 Pressure Control Solenoid 1 (PCS1) Control
Circuit—Performance (cont'd)
Step
16

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 PCS1 status on
TCM input wire 155.
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.

Value(s)

Yes

No

Go to Step 17

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?
17

To verify the repair:
1. Clear the DTC.
2. Drive the vehicle under conditions shown in
failure records.
Did DTC P2728 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 50 of 72

DTC P2762 TCC (PCS) Control Circuit—Performance

Circuit Description
The TCC PCS is a Pressure Proportional to Current (PPC) solenoid used to control the TCC apply and release.
The TCM sends control current to solenoid TCC from High Side Driver 1 (HSD1) via wire 111. HSD1 is continuously
on unless the TCM detects a fault condition. The TCM regulates the amount of current to the TCC by switching the
low side driver on and off. Wire 178 completes the circuit between the TCC and its low side driver. DTC P2762
indicates that the TCM processor has detected an open condition in the electrical circuit. The open condition may
exist in the high side (wire 111) or low side (wire 178).
Actions Taken When the DTC Sets
When DTC P2762 is active, the following conditions occur:
• 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 second consecutive occurrence.
• The DTC is stored in the TCM history.
• TCM inhibits Torque Converter Clutch (TCC) engagement.

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

SIL 14-TR-18
September, 2018
Page 51 of 72

DTC P2762 TCC (PCS) Control Circuit—Performance (cont'd)
NOTE: When connecting Allison DOC® to a General Motors Silverado 4500HD, 5500HD and 6500HD
models or a NAVISTAR CV model use J-48624 Translator and J-41788 OBD II Connector.
Conditions for Clearing the DTC
Use the Allison DOC® 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 J-39700 Universal Breakout, the J-48624 Translator and J-41788 OBD II Connector, and
appropriate magnetic overlays 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 the J-39700 Universal Breakout, the
J-48624 Translator and the J-41788 OBD II Connector with the Allison DOC® software 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 P2762 indicates an open, short to ground, short to power or wire to wire shorts in the electrical circuit
for the TCC solenoid.
• When this DTC sets there can be a noticeable reduction of engine performance.
• 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
• 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 open condition, 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 circuit ground condition.
Copyright © 2018 Allison Transmission, Inc. All Rights Reserved.

SIL 14-TR-18
September, 2018
Page 52 of 72

DTC P2762 TCC (PCS) Control Circuit—Performance (cont'd)
• 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. This step tests for the proper ignition voltage.
4. This step tests the OEM harness for an open condition in either wire 111 or wire 178 of the OEM chassis
harness.
5. This step tests the OEM harness for a wire to wire shorts condition in either wire 111 or wire 178 of the
OEM chassis harness.
6. This step tests the OEM harness for a short to ground condition in either wire 111 or wire 178 of the
OEM chassis harness.
7. This step tests the OEM harness for a short to power condition in either wire 111 or wire 178 of the
OEM chassis 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 TCC solenoid.
15. Recalibrate TCM with updated version of original calibration.
16. Install a test TCM.
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.

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

SIL 14-TR-18
September, 2018
Page 53 of 72

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

2

1.

3

1.
2.
3.

Connect the Allison DOC® software with the
J-48624 Translator and the J-41788 OBD
II Connector.
2. Start the engine.
3. Record the DTC failure record data.
4. Using the Allison DOC® software monitor
ignition voltage.
Is the voltage within the specified values?
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

Go to Step 3

Resolve voltage
problem. (Refer
to System
Voltage Low and
System Voltage
High)

Go to Step 5

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 TCC solenoid electrical
circuit.
Did DTC return?

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

SIL 14-TR-18
September, 2018
Page 54 of 72

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

Action

4

NOTE: Review WIRE CHECK PROCEDURES
before performing steps.

Value(s)

Yes

No

Go to Step 5

Go to Step 7

1.
2.

Turn ignition OFF.
Install the J-47275 TCM Breakout Harness
Adapter and the J-39700 Universal
Breakout Box on the TCM 80-way vehicle
wiring harness connector. Leave TCM
disconnected.
3. Remove the 24-way connector from the
transmission. At the 24-way transmission
harness connector install jumper wire from
pin 10 and 14, leave the transmission
disconnected.
4. On the J-39700 Universal Breakout Box,
measure pins 11 and 78 for continuity on
the J-47275-1 TCM Overlay.
Did the pins have continuity between them?

5

1.
2.
3.

Turn ignition OFF.
Disconnect the TCM 80-way connector.
Install the OEM side 80-way connector
to the Install the J-47275 TCM Breakout
Harness Adapter and the J-39700 Universal
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 11 and 78 and all other pins
on the J-47275-1 TCM Overlay.
Wire to wire continuity indicates a short
between OEM chassis wire 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 J-47275 TCM Breakout Harness
Adapter and J-47275-1 TCM Overlay
and J-39700 Universal Breakout Box on
the 80-way OEM connector. Leave TCM
disconnected.
3. Disconnect the 24-way transmission
connector.
4. On the J-39700 Universal Breakout Box,
measure pins 11 and 78 to ground on the
J-47275-1 TCM Overlay.
Was continuity measured between these pins
and chassis ground?

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

SIL 14-TR-18
September, 2018
Page 55 of 72

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

Action

Value(s)

Yes

No

7

1.
2.

Turn ignition OFF.
Install J-47275 the TCM Breakout Harness
Adapter and the J-47275-1 TCM Overlay
and the J-39700 Universal Breakout Box
on the 80-way OEM connector. Leave TCM
disconnected.
3. Remove the 24-way connector from the
transmission.
4. Turn ignition ON.
5. On the J-39700 Universal Breakout Box,
measure pins 11 and 78 to ground on the
J-47275-1 TCM Overlay.
Voltage on either pin indicates a short to power
in the wire harness. Was voltage measured?

Go to Step 8

Go to Step 8