Symptoms of malfunction - instrument panel, indicators
Important: The following steps must be completed before using the symptom tables.
1. Before using the symptom tables, perform a diagnostic check on the vehicle's system to ensure the following items are correct.
- There are no fault codes.
- The controllers can communicate over a serial line.
2. View system operation to familiarize yourself with the functions of the system.
Visual inspection / physical control
- Inspect aftermarket equipment that may affect the operation of the instrument cluster or warning horn systems.
- Inspect easily accessible and visible parts of the system for obvious signs of damage or conditions that could lead to a malfunction.
- Make sure the fluid level is correct.
Intermittent faults
Faulty electrical connections or wiring can cause intermittent faults. See paragraph "Checking for intermittent faults and poor contact in the connectors" in section 9A, "Body Wiring System".
Instrument cluster not working
Troubleshooting Information
- Before performing the diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
For instrument cluster (IPC) voltage is supplied by the battery voltage and ignition 1 voltage circuit. The IPC operates when the ignition 1 voltage circuit is in the RUN/START state.
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
1. Switch off the ignition, disconnect the IPC instrument cluster.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit and ground.
- If the test lamp does not illuminate, repair the short to ground or high resistance in the ignition 1 voltage circuit.
3. Verify that a test lamp illuminates between the ignition 1 voltage circuit and the IPC instrument cluster ground circuit.
- If the test lamp does not illuminate, repair the open or high resistance in the IPC instrument cluster ground circuit.
- If the test lamp is on, replace the IPC instrument cluster.
Repair Instructions
Perform a post-repair diagnostic check after completing the diagnostic procedure.
Controller information for replacement, tuning and programming of IPC and PCM.
Engine coolant temperature gauge is inaccurate or not working
Troubleshooting Information
Important: Before performing each diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
On the instrument cluster (IPC) engine coolant temperature is displayed according to data from the engine controller (ECM). The ECM sends temperature data over the GMLAN serial link to the body controller (BCM). The BCM sends data from GMLAN to the IPC to control the engine temperature gauge and display the engine coolant temperature.
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
Ignition ON, run a full range engine coolant temperature gauge check with a scan tool.
- If the engine coolant temperature gauge does not move across the range from low to high, replace the instrument cluster (IPC).
Repair Instructions
Important: Perform a Post-Repair Diagnostic Check at the end of each diagnostic procedure.
Information on the controller for replacing, setting and programming the IPC instrument cluster.
Fuel Gauge Shows Inaccurate Data or Doesn't Work
Troubleshooting Information
Important: Before performing each diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
The fuel level sensor changes resistance depending on the fuel level. Engine controller (ECM) monitors the signal circuit of the fuel level sensor to determine the fuel level. When the fuel tank is full, the sensor resistance is low and a low voltage signal is sent to the ECM. When the fuel tank is empty, the sensor resistance is high and a high voltage signal is sent to the ECM. The fuel level sensor signal circuit is used by the ECM to calculate the percentage of fuel remaining in the tank.
The ECM sends fuel level data via serial communication to the instrument cluster to control the fuel gauge. Fuel level data is also used to diagnose misfire and EVAP systems (EVAP).
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
1. Ignition OFF, disconnect CXXX, connect a signal generator and instrument cluster tester between the signal circuit and the low reference circuit.
2. Turn on the ignition, change the resistance on the signal generator from 40 to 250 ohms and observe the fuel gauge.
- If the fuel gauge reads the correct fuel level, test the signal circuit for an open or high resistance between CXXX and the fuel level sensor. If the circuits are OK, test the low reference circuit for an open or high resistance between CXXX and the fuel level sensor.
- If all circuits test normal, replace the fuel level sensor.
3. Turn on the ignition, change the resistance on the signal generator from 40 to 250 ohms. Make sure the setting is "Remaining fuel level in the tank" displays the correct percentage of fuel remaining in the tank.
- If the remaining fuel is displayed correctly, replace the instrument cluster (IPC).
- If the remaining fuel is not displayed correctly, test the signal circuit for an open or high resistance. If the circuits are OK, test the low reference circuit for an open or high resistance.
- If all circuits are normal, replace the ECM.
Repair Instructions
Important: Perform a Post-Repair Diagnostic Check at the end of each diagnostic procedure.
- "Fuel level sensor replacement" in section 1F2, "Engine Controls - FAM II 2.4D".
Inaccurate readings or speedometer and/or odometer not working
Troubleshooting Information
Important: Before performing each diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
On the instrument cluster (IPC) vehicle speed is displayed based on data from the engine controller (ECM). The ECM converts the data from the vehicle speed sensor into a signal of 4000 pulses per mile. The PCM sends vehicle speed data via the GMLAN serial link to the body controller (BCM). The BCM sends data from GMLAN to the IPC instrument cluster to control the speedometer and display vehicle speed and mileage.
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
1. Turn off the ignition, hang out the driving wheels of the car.
2. Start the engine, the gearbox in the drive position, check the compliance of the parameter "vehicle speed sensor" on the scan tool speedometer.
- If the parameter "vehicle speed sensor" does not match the speedometer reading, replace the IPC instrument cluster.
- If the trip meter is not working correctly, replace the IPC instrument cluster.
Repair Instructions
Important: Perform a Post-Repair Diagnostic Check at the end of each diagnostic procedure.
Inaccurate readings or tachometer not working
Troubleshooting Information
Important: Before performing each diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
On the instrument cluster (IPC) engine speed is displayed based on data from the engine controller (ECM). The ECM converts the data from the vehicle speed sensor into a signal of 2 pulses per engine revolution. The ECM sends engine speed data via serial communication to the body controller (BCM). The BCM sends data from GMLAN to the IPC instrument cluster to control the tachometer pointer and display engine speed.
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
Turn off the ignition, hang out the driving wheels of the car.
- If the tachometer pointer does not move across the entire range from the lower position to the upper position, replace the instrument cluster (IPC).
Repair Instructions
Important: Perform a Post-Repair Diagnostic Check at the end of each diagnostic procedure.
Sound alarm constantly on
Troubleshooting Information
Important: Before performing each diagnostic procedure, perform a Diagnostic System Check on the vehicle.
Circuit/system description
The audio system beeps continuously through the left front speaker. Audio warning chimes are commanded via a serial link from the body controller (BCM).
Electrical information
- Circuit Check
- Connector repair
- Checking for intermittent faults and poor contact in the connectors
- Wiring repair
Circuit/System Check
1. Turn the ignition on, turn the headlight switch to the OFF position, make sure that the parameter "headlight switch" on the scan tool indicates an inactive state.
- If the switch is inactive, test the headlight signal circuit for an open or short to voltage. If the circuit is OK, replace the headlight switch.
2. Switch off the ignition, remove the key from the ignition lock, make sure that the parameter "Ignition key insertion status" on the scan tool indicates that the key is removed.
- If the parameter does not indicate that the key is out, test the signal circuit of the key out control switch for an open or short to voltage. If the circuit is OK, replace the ignition switch.
3. Switch off the ignition, remove the key from the ignition lock, make sure that the parameter "Ignition key insertion status" on the scan tool indicates that the key is removed.
- If any of the parameters show "The door is ajar", go to section "Entrance lights are constantly on".
- If all parameters show "The door is closed", replace the BCM.
Repair Instructions
Important: Perform a Post-Repair Diagnostic Check at the end of each diagnostic procedure.
- Ignition switch replacement
- Replacing the multifunction turn signal switch.