B0560

DTC B0560

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B0560
- Tachometer Circuit

Diagnostic Fault Information






Circuit Description

The instrument panel cluster (IPC) receives the engine speed information from the engine control module (ECM)/powertrain control module (PCM) through the engine speed signal circuit. The ECM/PCM converts the data from the engine speed sensor to a 2 pulses/engine revolution signal. The ECM/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 ECM/PCM due to a engine speed signal circuit malfunction, a DTC sets.

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.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X1 at the ECM/PCM. Install a signal generator and instrument panel tester between the following engine speed signal circuit and ground:

* Terminal 31 (4.2L)
* Terminal 25 (5.3L/6.0L)

2. Ignition ON, set the signal generator to generate a tachometer signal. Verify that the tachometer indicates a RPM reading.

^ If no RPM reading is present, test the signal circuit for an open/high resistance, a short to voltage, or a short to ground. If the circuit tests normal, replace the IPC.

3. If all circuits test normal, test or replace the ECM/PCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests