Diesel Data: Automotive Repair
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P0753















Circuit Description

The 1-2 shift solenoid valve controls transmission fluid to the 1-2 shift valve. Ignition voltage is provided to the solenoid. The PCMs Output Driver Module (ODM) provides the ground. When the 1-2 shift solenoid valve is commanded ON, the PCM senses 0 volts. When the 1-2 shift solenoid valve is commanded OFF, the PCM senses ignition voltage. When the PCM detects voltage limits that do not meet the calibration, then DTC P0753 sets. DTC P0753 is a Type A DTC.


Conditions for Setting the DTC

^ No ODM DTC P1650 set.

^ The engine has been running for more than 5 seconds.

^ The PCM detects an open, a short to ground, or a short to power on the 1-2 shift solenoid valve circuits within 5 seconds.


Action Taken When the DTC Sets

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ SERVICE ENGINE SOON displays on the Driver Information Center (DIC).

^ The PCM commands 2nd gear.

^ The PCM commands default line pressure.

^ The PCM disables steady state adapts.

^ The PCM disables garage shift adapts.

^ The PCM inhibits Torque Converter Clutch.

^ The PCM inhibits torque management.

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.


Diagnostic Aids

^ Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Inspect the wiring for poor electrical connections at the 1-2 shift solenoid valve connector. Look for the following conditions:

- A bent terminal

- A backed out terminal

- A damaged terminal

- Poor terminal tension

- A chafed wire

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

Test Description

The numbers below refer to the step numbers on the diagnostic chart.

1. This Step verifies that you performed the Powertrain On-Board Diagnostic System Check.

3. This Step inspects the SHIFT SOLENOID fuse for an open.

4. This Step verifies that an open fuse was caused by a short to ground in circuit 339.

5. This Step verifies that the fuse was not open and that circuit 339 must be inspected for an open.

6. This Step verifies that the 1-2 Shift Solenoid Valve is operating and that an intermittent condition may have set the DTC.

7. This Step isolates the Automatic Transmission Wiring Harness so that you can diagnose the Engine Wiring Harness. Use the J 35616 Connector Test Adapter Kit, in order to avoid damaging the terminals.

8. This Step verifies that the test lamp is ON and that circuit 1222 of the Engine Wiring Harness has been Inspected for a short to ground.

9. This Step isolates circuit 1222 for an open.

10. This Step verifies that the test lamp is OFF and that circuit 1222 of the Engine Wiring Harness has been Inspected for an open.

11. This Step isolates circuit 1222 of the Engine Wiring Harness for a short to power.

12. This Step verifies that the test lamp is OFF and that no open was found in circuit 1222. The Engine Wiring Harness is Inspected for a short to power.

13. This Step isolates the Engine Wiring Harness so that you may diagnose the Automatic Transmission Wiring Harness. Use the J 35616 Connector Test Adapter Kit, in order to avoid damaging the terminals.

14. This Step measures a resistance value above the high parameter.

15. This Step inspects circuit 741 and circuit 1222 for an open. If you find an open in the transmission harness, you must replace the hamess.

16. This Step measures for a short to ground in circuit 1222.

17. This Step verifies that the resistance is less than 100 ohms and that circuit 1222 has been Inspected for a short to ground. If you find a short to ground in the transmission harness, you must replace the harness.

18. This Step replaces the 1-2 Shift Solenoid Valve after you have inspected all the circuits.

19. This Step replaces the PCM after you have validated all the circuits and components.

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