GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2003 🢒 Ascender - 4WD 🢒 DTC 🢒 DTC B0540

Circuit Description

The IPC monitors the vehicle speed signal to determine the speedometer position. If the IPC determines the vehicle speed signal voltage is out of the normal operating range, a DTC will set.

Conditions for Running the DTC
    • The vehicle speed is more than 10 km/h (6 mph).
    • The ignition voltage is between 9.0 volts and 18.0 volts.

Conditions for Setting the DTC
    • The IPC detects that the commanded state of the output driver and the actual state of the control circuit do not match.
    • The condition above must be present for a minimum of 5 seconds.

Action Taken When the DTC Sets
    • The IPC stores a DTC B0540 in memory.
    • The speedometer defaults to 0 km/h (0 mph).
    • No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC
    • The history DTC clears after 100 malfunction free warm-up cycles.
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The IPC receives the clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views , Powertrain Control Module Connector End Views , or Powertrain Control Module Connector End Views

1

Did you perform the IPC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2
  1. Install a scan tool.
  2. Raise the vehicle's drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Start the engine.
  4. Place the transmission into drive for an automatic transmission and third gear for a manual transmission.
  5. With the scan tool, observe the Vehicle Speed parameter in the PCM Engine Data 1 data list.

Does the Vehicle Speed parameter match the speedometer display?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3
  1. Turn the ignition OFF.
  2. Disconnect the following PCM connector:
    3. • C1 (LL8)
    • C2 (LM4)
  3. Install the J 33431-C Signal Generator and Instrument Panel Tester lead to the vehicle speed signal circuit at the PCM harness connector, and the other lead to a good ground.
  4. Turn the ignition ON, with the engine OFF.
  5. Set the J 33431-C to generate a speedometer signal.

Does the vehicle speedometer indicate a reading?

Go to Step 5

Go to Step 4

4

Test the vehicle speed signal circuit for an open, short to voltage or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the PCM connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for a poor connection at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Important: Program the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.2L or to Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L, or 6.0L.

Did you complete the replacement?

Go to Step 9

--

8

Important: Program the replacement IPC

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 9

--

9
  1. Use the scan tool in order to clear the DTC's.
  2. Operate vehicle within the conditions for running this DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK