For 1990-2009 cars

## Check Gages Indicator Always On L18 8.1L Gasoline Engine

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Instrument Cluster Schematics
1 | Did you perform the Instrument Panel Cluster Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Instrument Cluster
2 |

1. Start the engine.
2. Observe the CHECK GAGES indicator in the instrument panel cluster (IPC).

Does the CHECK GAGES indicator turn OFF after the displays test?

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

Go to Step 3

3 |

1. Turn the ignition OFF.
2. Disconnect C210.
3. Start the engine.
4. Observe the CHECK GAGES indicator in the IPC.

Does the CHECK GAGES indicator illuminate in the IPC?

Go to Step 4

Go to Step 5

4 |

1. Turn the ignition OFF.
2. Disconnect the multifunction alarm module (MFAM) connector C1.
3. Start the engine.
4. Observe the CHECK GAGES indicator in the IPC.

Does the CHECK GAGES indicator illuminate in the IPC?

Go to Step 6

Go to Step 7

5 | Test the check gages indicator control circuit for a short to ground between C210 and the PCM. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9
6 | Test the check gages indicator control circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 8
7 | Inspect for poor connections at the harness connector of the MFAM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10
8 | Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11
9 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12
10 | Replace the MFAM. Refer to Multifunction Alarm Module Replacement . Did you complete the replacement? | Go to Step 13 | --
11 | Replace the IPC. Refer to Instrument Cluster Replacement . Did you complete the replacement? | Go to Step 13 | --
12 | Important:: Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2

## Check Gages Indicator Always On 7.2L Diesel Engine LG5

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Instrument Cluster Schematics
1 | Did you perform the Instrument Panel Cluster Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Instrument Cluster
2 |

1. Start the engine.
2. Observe the CHECK GAGES indicator in the instrument panel cluster (IPC).

Does the CHECK GAGES indicator turn OFF after the displays test?

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

Go to Step 3

3 |

1. Turn the engine OFF.
2. Disconnect the engine oil pressure (EOP) switch.
3. Start the engine.
4. Observe the CHECK GAGES indicator in the IPC.

Does the CHECK GAGES indicator turn OFF after the displays test?

Go to Step 9

Go to Step 4

4 |

1. Turn the engine OFF.
2. Disconnect the engine coolant temperature (ECT) switch.
3. Start the engine.
4. Observe the CHECK GAGES indicator in the IPC.

Does the CHECK GAGES indicator turn OFF after the displays test?

Go to Step 10

Go to Step 5

5 | Test the signal circuit of the EOP switch for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 6
6 | Test the signal circuit of the ECT switch for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 7
7 |

1. Turn the engine OFF.
2. Disconnect the multifunction alarm module (MFAM).
3. Start the engine.
4. Observe the CHECK GAGES indicator in the IPC.

Does the CHECK GAGES indicator turn OFF after the displays test?

Go to Step 11

Go to Step 8

8 | Test the check gages indicator control circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 12
9 | Inspect for poor connections at the harness connector of the EOP switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 13
10 | Inspect for poor connections at the harness connector of the ECT switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 14
11 | Inspect for poor connections at the harness connector of the MFAM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 15
12 | Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 17 | Go to Step 16
13 | Replace the EOP switch. Refer to the Cat® Medium Duty Diesel Engine Manual - LG5. Did you complete the replacement? | Go to Step 17 | --
14 | Replace the ECT switch. Refer to the Cat® Medium Duty Diesel Engine Manual - LG5. Did you complete the replacement? | Go to Step 17 | --
15 | Replace the MFAM. Refer to Multifunction Alarm Module Replacement . Did you complete the replacement? | Go to Step 17 | --
16 | Replace the IPC. Refer to Instrument Cluster Replacement . Did you complete the replacement? | Go to Step 17 | --
17 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2