GM Service Manual Online
For 1990-2009 cars only

DTC P0500 3.0L

Circuit Description

The engine control module (ECM) receives vehicle speed through high-speed communications on the controller area network (CAN) from the transmission control module (TCM) with ABS based on the output speed sensor (OSS) and from the wheel speed sensor conditioner without ABS based on the right front wheel speed sensor. The OSS is attached to the top rear of the transmission case and the right front wheel speed sensor is attached to the right front hub assembly. The sensor produces an AC current generated as the output shaft rotates with ABS and as the right front drive axle rotates without ABS. The ECM continuously monitors the vehicle speed signal.

If the ECM does not detect a sufficient amount of vehicle speed from the TCM or the wheel speed sensor conditioner over the CAN link when engine speed is above a certain range while the vehicle is in fourth of fifth gear, DTC P0500 sets. DTC P0500 is a type B DTC.

Conditions for Running the DTC

    • No CAN DTCs U2103 or U2105.
    • The engine speed is 1,800-3,000 RPM.
    • The ECM deceleration fuel shutoff is active.
    • The engine coolant temperature is greater than 64°C (147°F).
    • The TCM commanded gear is 4th or 5th.

Conditions for Setting the DTC

The vehicle speed is less than 5 km/h (3 mph) for a total of 3 seconds.

Action Taken When the DTC Sets

    • The ECM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
    • The ECM stores DTC P0500 in ECM history.

Conditions for Clearing the DTC

    • The ECM turns off the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool can clear the DTC.
    • The ECM clears the DTC from ECM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.

Diagnostic Aids

    • If TCM DTCs P0502 or P0503 are set, diagnose these DTCs first.
    • If an output speed sensor signal circuit fault is occurring, a vehicle speed of 0 km/h (0 mph) will be sent to the ECM and the ECM will set DTC P0500.
    • To locate an intermittent problem, use the scan tool to monitor vehicle speed in the ECM data list with the vehicle raised and the drive wheels moving greater than 5 km/h (3 mph). If an intermittent output speed sensor signal is occurring, vehicle speed on the scan tool will go to 0 km/h (0 mph).

Test Description

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

  1. Because the TCM supplies the ECM with vehicle speed, the TCM will also have set a DTC.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Functional Diagnostic Procedure?

Go to Step 2

Go to Functional Diagnostics

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Important: Before clearing the DTC, use the scan tool in order to record the ECM Freeze Frame and the TCM Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the ECM and the TCM.

  4. Record the Freeze Frame and Failure Records.

Did you record Freeze Frame or Failure Records for any of the following communication codes: U2103 or U2105?

Go to DTC U2103 and/or DTC U2105-U2108 in Data Link Communications

Go to Step 3

3

Did you record Freeze Frame or Failure Records for DTCs P0502 or P0503?

Go to DTC P0502 or DTC P0503

Go to Automatic Transaxle Complaint/Condition Chart