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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Optra 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0785

DTC P0785 Non European Emissions

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0785 3-2 Shift Solenoid (SS) Control Circuit

Conditions for Setting the DTC
    • The transmission control module (TCM) detects that the ON signal of the timing solenoid monitor during 0.5 seconds when the timing solenoid driver outputs the OFF signal. The timing solenoid circuit is open or short to battery.
    • The TCM detects that the OFF signal of the timing solenoid monitor during 0.1 seconds when the timing solenoid driver outputs the ON signal. The timing solenoid circuit is short to battery.
    • The above detection 3 times at shifting continuously.

Action Taken When the DTC Sets
    • TCM will request the illumination of the hold lamp and store the DTC when the TCM detects a failure on the 1st ignition cycle
    • After failure decision: emergency mode

Conditions for Clearing the DTC
    • The TCM turns off the hold lamp when no further failures are detected on the next ignition cycles.
    • The scan tool can clear the DTC from the TCM history.
    • The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.
    • The TCM detects the ON signal of the timing solenoid monitor during 100 ms when the timing solenoid driver outputs the ON signal and TCM detects the OFF signal of the timing solenoid monitor during 160 ms when the timing solenoid driver outputs the OFF signal.

Cause of Failure
    • Wiring harness or connector between timing solenoid and TCM
    • Timing solenoid
    • TCM

Step

Action

Value(s)

Yes

No

1
  1. Turn OFF the ignition.
  2. Install the scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Select Store Freeze Frame/Failure Records from the Diagnostic Trouble Codes Information menu.
  5. Store Freeze Frame/Failure Records.
  6. Select Clear DTC Information from the Diagnostic Trouble Codes Information menu.
  7. Clear DTC Information.
  8. Perform 1 vehicle drive cycle.

Is the hold lamp ON?

--

Go to Step 2

Go to Step 4

2
  1. Select Request DTC by Status from the Diagnostic Trouble Codes Information menu.
  2. Request DTC by Status.

Is DTC P0785 displayed?

--

Go to Step 3

Go to Step 4

3
  1. Turn OFF the ignition.
  2. Measure the resistance between the vehicle harness and timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .
  3. Disconnect the transmission control module (TCM) connector and measure the resistance between the terminal A24 and A23.

Is the measurement within the specified values?

20°C (68°F)

11-16 ohms

Go to Step 5

Go to Step 6

4

Repair the temporary connection failure of the connector. Refer to Wiring Harness and Connector Inspection Diagnosis .

Did you complete the repair?

--

System OK

--

5
  1. Estimate the failure of between the vehicle wiring harness connector and TCM.
  2. Inspect the connector. Refer to Wiring Harness and Connector Inspection Diagnosis .
  3. Inspect the connection condition between the connectors.

Is the connection condition OK?

--

Go to Step 7

Go to Step 4

6
  1. Estimate the failure of between the vehicle harness and timing solenoid.
  2. Disconnect the transaxle harness connector and measure the resistance between the timing solenoid connector terminal 2 and ground.

Is the measurement within the specified values?

20°C (68°F)

11-16 ohms

Go to Step 8

Go to Step 9

7
  1. Replace the TCM. Refer to Transmission Control Module Replacement .
  2. Perform the reproducing test under user condition after confirming no DTC.

Is DTC displayed?

--

Go to Step 1

System OK

8
  1. Estimate the failure of the vehicle wiring harness or between connectors.
  2. Test continuity and short circuit for the vehicle wiring harness and inspect the connection condition between connectors. Refer to Wiring Harness and Connector Inspection Diagnosis .

Is the condition OK?

--

Go to Step 4

Go to Step 12

9
  1. Estimate the failure of the transaxle harness between connectors of timing solenoid.
  2. Inspect the timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .

Is the problem found?

--

Go to Step 11

Go to Step 10

10
  1. Estimate the failure of the transaxle harness.
  2. Test continuity and short circuit the transaxle harness and inspect the connection condition between connectors. Refer to Wiring Harness and Connector Inspection Diagnosis .

Is the condition OK?

--

Go to Step 4

Go to Step 13

11

Replace the timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .

Did you complete the replacement?

--

System OK

--

12

Repair or replace the vehicle harness.

Did you complete the repair?

--

System OK

--

13

Replace the transaxle harness.

Did you complete the replacement?

--

System OK

--

DTC P0785 European Emissions

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0785 3-2 Shift Solenoid (SS) Control Circuit

Conditions for Setting the DTC
    • The transmission control module (TCM) detects that the ON signal of the timing solenoid (ST) monitor during 0.5 seconds when the timing solenoid driver outputs the OFF signal. The timing solenoid circuit is open or short to battery.
    • The TCM detects that the OFF signal of the timing solenoid monitor during 0.1 seconds when the timing solenoid driver outputs the ON signal. The timing solenoid circuit is short to battery.
    • The above detection 3 times at shifting continuously.

Action Taken When the DTC Sets
    • TCM will request the illumination of the malfunction indicator lamp (MIL) and store the DTC when the TCM detects a failure on the 1st ignition cycle
    • After failure decision: emergency mode

Conditions for Clearing the DTC
    • The TCM turns off the MIL when no further failures are detected on the next ignition cycles.
    • The scan tool can clear the DTC from the TCM history.
    • The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.
    • The TCM detects the ON signal of the timing solenoid monitor during 100 ms when the timing solenoid driver outputs the ON signal and TCM detects the OFF signal of the timing solenoid monitor during 160 ms when the timing solenoid driver outputs the OFF signal.

Cause of Failure
    • Wiring harness or connector between timing solenoid and TCM
    • Timing solenoid
    • TCM

Step

Action

Value(s)

Yes

No

1
  1. Turn OFF the ignition.
  2. Install the scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Select Store Freeze Frame/Failure Records from the Diagnostic Trouble Codes Information menu.
  5. Store Freeze Frame/Failure Records.
  6. Select Clear DTC Information from the Diagnostic Trouble Codes Information menu.
  7. Clear DTC Information.
  8. Perform 1 vehicle drive cycle.

Is the malfunction indicator lamp (MIL) ON?

--

Go to Step 2

Go to Step 4

2
  1. Select Request DTC by Status from the Diagnostic Trouble Codes Information menu.
  2. Request DTC by Status.

Is DTC P0785 displayed?

--

Go to Step 3

Go to Step 4

3
  1. Turn OFF the ignition.
  2. Measure the resistance between the vehicle harness and timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .
  3. Disconnect the transmission control module (TCM) connector and measure the resistance between the terminal A24 and A23.

Is the measurement within the specified values?

20°C (68°F)

11-16 ohms

Go to Step 5

Go to Step 6

4

Repair the temporary connection failure of the connector. Refer to Wiring Harness and Connector Inspection Diagnosis .

Did you complete the repair?

--

System OK

--

5
  1. Estimate the failure of between the vehicle wiring harness connector and TCM.
  2. Inspect the connector. Refer to Wiring Harness and Connector Inspection Diagnosis .
  3. Inspect the connection condition between the connectors.

Is the connection condition OK?

--

Go to Step 7

Go to Step 4

6
  1. Estimate the failure of between the vehicle harness and timing solenoid.
  2. Disconnect the transaxle harness connector and measure the resistance between the timing solenoid connector terminal 2 and ground.

Is the measurement within the specified values?

20°C (68°F)

11-16 ohms

Go to Step 8

Go to Step 9

7
  1. Replace the TCM. Refer to Transmission Control Module Replacement .
  2. Perform the reproducing test under user condition after confirming no DTC.

Is DTC displayed?

--

Go to Step 1

System OK

8
  1. Estimate the failure of the vehicle wiring harness or between connectors.
  2. Test continuity and short circuit for the vehicle wiring harness and inspect the connection condition between connectors. Refer to Wiring Harness and Connector Inspection Diagnosis .

Is the condition OK?

--

Go to Step 4

Go to Step 12

9
  1. Estimate the failure of the transaxle harness between connectors of timing solenoid.
  2. Inspect the timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .

Is the problem found?

--

Go to Step 11

Go to Step 10

10
  1. Estimate the failure of the transaxle harness.
  2. Test continuity and short circuit the transaxle harness and inspect the connection condition between connectors. Refer to Wiring Harness and Connector Inspection Diagnosis .

Is the condition OK?

--

Go to Step 4

Go to Step 13

11

Replace the timing solenoid. Refer to 1, 2 Shift Solenoid, Timing Solenoid, and Lock-Up Solenoid Inspection .

Did you complete the replacement?

--

System OK

--

12

Repair or replace the vehicle harness.

Did you complete the repair?

--

System OK

--

13

Replace the transaxle harness.

Did you complete the replacement?

--

System OK

--