Troubleshooting Hints - Gauges and Warning Indicators

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Check SBM/LCM fuse in the engine compartment power distribution center by visual inspection.
2. Check PCM/CRU fuse in the rear power distribution center by visual inspection.
3. If more than one indicator or gauge is out, check common power and ground inputs.
4. Before component replacement, check for poor connections component and connector terminal connections. (Refer to General Troubleshooting Procedures.) Diagnostic Aids

DIAGNOSTIC TROUBLE CODES (DTCs)
Diagnostic Trouble Codes (DTCs), when set, indicate that the Instrument Panel Cluster (IPC) has detected a malfunction in a particular circuit or other system. The IPC is programmed with routines for internal checks that it follows only under prescribed conditions (called Test Conditions). When these conditions exist, the IPC checks certain circuits or systems for a malfunction. These checks are called failure conditions. When the failure conditions are true, a DTC is set. Some DTCs alert the driver through a Service Vehicle soon indicator.

Diagnostic Trouble Codes are not stored in the IPC's EEPROM and therefore will not be retained after a battery disconnect, either from the vehicle or just the IPC.

CURRENT DTC:
When the IPC determines that the test conditions and failure conditions for a particular DTC are true, it sets that DTC as 'Current'. All DTCs remain current at least until the next time the IPC finds the test conditions are true and the failure conditions are false. A few DTCs remain current until the next ignition cycle or until the failure conditions are false several times.

HISTORY DTC:
After a DTC has been set, the IPC continues to monitor for the test and failure conditions. For most DTCs, if the test conditions are true and the failure conditions are false, the DTC is changed to history. Some DTCs require the test conditions to be true and failure conditions false several times or require an ignition cycle to change from current to history. If there are no current DTCs for a period of 50 ignition cycle, all history DTCs will be cleared.

DIAGNOSTIC TROUBLE CODE (DTC) DIAGNOSIS
This uses diagnostic charts, wiring diagrams and descriptive text to direct you in performing specific tests to locate and repair the problem. The diagnostic chart is a step by step procedure to determine the circuit or component that is the source of the problem. The wiring diagrams and text describing the system, test conditions, failure conditions and actions taken when a DTC is set are located on the page facing the diagnostic chart. Refer to 'IPC Diagnosis Procedure' for details.

DIAGNOSTIC TROUBLE CODE DISPLAY
The use of a diagnostic scan tool is required to display IPC DTC's.

IPC CLEAR CODES
The use of a scan tool is required to clear stored IPC DTCs. When selected, the IPC Clear Codes option immediately erases all DTCs stored up to that point. Once a malfunction has been corrected, clear DTCs so that any future service work is not needlessly confused.

Many IPC DTCs have complex test and failure conditions. Therefore, simply clearing DTCs and watching to see if the DTC sets again, may not indicate whether a malfunction has been corrected. To verify a repair after it is complete, you must look up the test conditions (located on the facing page of the trouble chart) and duplicate those conditions.