For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: In order to avoid misdiagnosis, check for powertrain control module (PCM) DTCs before performing this diagnosis. Refer to Powertrain On Board Diagnostic (OBD) System Check (V6 VIN K) or Powertrain On Board Diagnostic (OBD) System Check (V8 VIN G).
1 |

1. Disconnect the powertrain control module (PCM) connector C1 (V6 VIN K) or C2 (V8 VIN G).
2. Connect a J 33431-C signal generator and instrument cluster tester to the PCM connector circuit 817.
3. Set the J 33431-C to 54 mph.
4. Turn the ignition switch to the RUN position.

Does the speedometer measure approximately 54 mph (87 kph)?

54 mph (87 kph)

Go to Step 2

Go to Step 3

2 |

1. Check circuit 817 for a poor connection at the PCM.
2. If OK, replace the PCM. Refer to Powertrain Control Module Replacement/Programming (V6 VIN K) or Powertrain Control Module Replacement/Programming (V8 VIN G).

Is the repair complete?

--

System OK

--

3 |

1. Disconnect the instrument cluster.
2. Connect a test lamp from the PCM connector circuit 817 to ground.

Does the test lamp light?

--

Go to Step 4

Go to Step 5

4 | Repair the short to B+ in circuit 817. Is the repair complete? | -- | System OK | --
5 | Connect a test lamp from PCM connector circuit 817 to B+. Does the test lamp light? | -- | Go to Step 6 | Go to Step 7
6 | Repair the short to ground in circuit 817. Is the repair complete? | -- | System OK | --
7 |

1. Connect a fused jumper from the PCM connector circuit 817 to ground.
2. Connect a test lamp from the instrument cluster connector circuit 817 to B+
3. Does the test lamp light?

--

Go to Step 8

Go to Step 9

8 |

1. Check circuit 817 for a poor connection at the instrument cluster.
2. If the connection is OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

--

System OK

--

9 | Repair the open or poor connection in circuit 817 between the instrument cluster and the PCM. Is the repair complete? | -- | System OK | --