GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Vivant 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - ZF 4HP 16 🢒 DTC P0781

Circuit Description

The special feature of a 4HP 16 automatic transaxle is that it operates without freewheels. Shifting between individual gears takes place by means of overlapping clutch engagement and release.

The advantages of overlap shifting are as follows:

    • The transaxle can be a more compact design and is lighter on account of the absence of freewheels and the lower number of shift elements.
    • Lower drag losses, i.e., higher efficiency
    • Lower peak torque acting on the components and driveline

However, overlap shifting necessitates high-performance hardware and software, and precision engine signals.

Conditions for Setting the DTC
    • The transmission oil temperature is greater than -10°C (+14°F).
    • The selector lever is not in the neutral (N) or park (P) position.
    • System voltage is greater than 9 volts.
    • No input speed error DTCs P0715, P0716, and P0717 are set.
    • The output speed is greater than 256 RPM.
    • The input speed is greater than 400 RPM.
    • The 1-2 gear shift is active.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will illuminate.
    • The transmission control module (TCM) will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.
    • Adopt Emergency/Substitute mode and constant 1st gear.
    • Open lock up clutch

Conditions for Clearing the MIL/DTC
    • The MIL lamp will turn OFF when the malfunction has not occurred after 3 ignition cycles.
    • A history DTC will clear after 40 consecutive warm-up cycles without a fault.
    • Using a scan tool can clear history DTCs.

Diagnostic Aids

When DTC P0781 sets, the possible cause of fault could be the TCM.

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install the scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Start the engine and allow it to warm up at idle.
  4. Observe the idle RPM, TPS on the scan tool.

Was the condition found and corrected?

--

System OK

Go to Step 3

3

Inspect the electronic control module (ECM).

Was a condition found?

--

Go to Engine Control Module Replacement for the 2.0L engine

Go to Step 4

4
  1. Turn the ignition OFF.
  2. Disconnect the transmission control module (TCM) wiring connector.
  3. Measure the voltage between terminal B3 and B13 of the transaxle wiring connector.
  4. Turn the ignition ON.
  5. Measure the voltage between the terminal C15 and B13 of the transaxle wiring connector.
  6. Measure the voltage between terminal C16 and B13 of the transaxle wiring connector.

Is the voltage within the specified values?

11-14 V

Go to Step 5

Go to DTC P0562 or DTC P0563

5

Replace the TCM. Refer to Transmission Control Module Replacement.

Did you complete the replacement?

--

Go to Step 6

--

6
  1. Clear the DTCs with a scan tool.
  2. Road test the vehicle.
  3. Observe the DTC information with a scan tool.

Has the last test failed or is the current DTC displayed?

--

Go to Step 7

System OK

7

Replace the transaxle assembly. Transmission Replacement .

Did you complete the replacement?

--

Go to Step 8

--

8
  1. Clear the DTCs with a scan tool.
  2. Road test the vehicle.
  3. Observe the DTC information with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Step 2

System OK