GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2005 🢒 Ascender - 2WD 🢒 DTC 🢒 DTC B0560

Circuit Description

The instrument panel cluster (IPC) receives the engine speed information from the powertrain control module (PCM) through the engine speed signal circuit. The PCM converts the data from the engine speed sensor to a 2 pulses/(engine revolution) signal. The PCM also sends a class 2 message to the IPC indicating the engine speed. If the IPC determines there is a loss of the engine speed signal from the PCM due to a engine speed signal circuit malfunction, a DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B0560 Tachometer Circuit

Conditions for Running the DTC
    • The engine speed is greater than 800 RPM.
    • The ignition voltage is greater than 9 volts, but less than 18 volts.

Conditions for Setting the DTC
    • The IPC detects that the engine speed signal circuit does not match the engine speed from the class 2 serial data circuit.
    • The above condition is present for at least 5 seconds.

Action Taken When the DTC Sets

The IPC stores the DTC in memory.

Conditions for Clearing the DTC
    • A last test failed (current DTC) clears when the diagnostic runs and does not fail.
    • A history DTC clears after 100 consecutive malfunction-free warm-up cycles.
    • The IPC receives the clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install a scan tool.
  2. Start the engine.
  3. With the scan tool, observe the Engine Speed parameter in the IPC Data 1 data list.

Does the Engine Speed parameter match the tachometer display?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Turn the ignition OFF.
  2. Disconnect the powertrain control module (PCM) connector C2.
  3. Install the J 33431-C Signal Generator and Instrument Panel Tester lead to the engine 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 tachometer signal.

Does the vehicle tachometer indicate an RPM reading?

Go to Step 5

Go to Step 4

4

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

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 .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7

Replace the PCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

8

Replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

9
  1. Use the scan tool in order to clear the DTCs.
  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