Instrument Panel Cluster (IPC) - Diagnostic Mode Operation
Diagnostic Mode OperationTo enter the instrument cluster Diagnostic Mode, press the trip computer switch MODE and SET buttons simultaneously while turning the ignition on. Further pressing the MODE button for less than 2 seconds will step through the various instrument cluster information displays, which appear on the MFD. The vehicle may be driven while in Diagnostic Mode. As the instrument cluster can be set to display either English (miles per hour) or Metric (kilometers per hour), the screens displayed in Diagnostic Mode will depend on that selection.
To exit the instrument cluster Diagnostic Mode press the trip computer switch SET button for less than 2 seconds, or switch the ignition off. In sequence, the instrument cluster Diagnostic Mode screens are:
Software Version
This screen provides details of the instrument cluster software version.
Press the MODE button to continue.
GM Part Number
This screen provides details of the instrument cluster part number.
Press the MODE button to continue.
Trip Computer Switch Voltage
This screen provides an indication of the operational status of the trip computer switch. When checking the MODE button voltage, press and hold the button for more than 2 seconds otherwise the Diagnostic Mode will advance to the Battery Voltage screen. When checking the SET button voltage, press and hold the button for more than 2 seconds otherwise the system will exit the Diagnostic Mode.
Press each button and the following nominal voltages should be indicated:
- MODE button-3.9 V to 4.28 V
- SET button-4.28 V to 4.75 V
- UP button-3.26 V to 3.55 V
- DOWN button-2.43 V to 2.71 V
Press the MODE button to continue.
Battery Voltage
This screen provides an indication of the current battery voltage.
Press the MODE button to continue.
Fuel Calibration Part Number
When an instrument cluster is replaced, the fuel calibration pant number is to be entered using Tech 2. This identifies the fuel tank size and fuel sender unit resistance to the instrument cluster.
Press the MODE button to continue.
Remaining Fuel
This screen provides an estimate of the fuel remaining in the fuel tank to the nearest gallon (5 liters). Remaining fuel can also be displayed in gallons.
Press the MODE button to continue.
Instantaneous Fuel
This screen provides details of the instantaneous fuel usage. Instantaneous fuel can also be displayed in gallons per hour.
Press the MODE button to continue.
Coolant Temperature
This screen provides an indication of the current coolant temperature in degrees Celsius. The current coolant temperature can also be displayed in degrees Fahrenheit.
Press the MODE button to continue.
Speed
This screen provides an indication of the current vehicle speed in kilometers per hour. The current vehicle speed can also be displayed in miles per hour.
Press the MODE button to continue.
Tacho
This screen provides an indication of the current engine speed in RPM.
Press the MODE button to continue.
Park Lamps On/Off
The park lamps circuit provides illumination for the instrument cluster. If the parks lamps are shown as ON, the instrument cluster should also be illuminated.
Press the MODE button to continue.
Daytime Running Lamps
The daytime running lamps circuit provides illumination of the low beam headlamps when the following conditions are satisfied: PRNDL not in Park (Automatic transmission only). Park brake is released. Vehicle speed exceeds 11 km/h (7 MPH) Park lamps are off.
Press the MODE button to continue.
Trouble Codes
The Trouble Codes screen displays 2 rows of 16 digits each. If no DTC is set the 32 digits are all zeros (0). However, if a DTC is set, this is represented by a one (1) in the appropriate position in the rows. The following table shows the location of each DTC identifying digit. To determine the actual DTC number that has been set, count the digits from the bottom right hand side, starting at zero.
Press the MODE button to continue.
Full Test
The Diagnostic Mode also has a self-test function (Full Test) to verify correct instrument cluster operation.
When activated, the following occurs:
- The temperature Gauge and the fuel Gauge are set to the halfway mark (50%).
- The tachometer is set to 3,000 RPM.
- The speedometer is set to 70 MPH or 70 km/h.
- The chime is activated at 1 kHz.
- The warning indicator LEDs that are driven by either the internal microprocessor or from the serial data line are illuminated. These are Airbag, Brake Park/Fail, Seat Belt and Shift 1 - 4.
- All segments of the MFD and the side LCDs are illuminated.
- Press the MODE button to return to the GM Pant Number screen, or the SET button to exit the instrument cluster Diagnostic Mode.
Faults can be identified by using Tech 2 to test instruments and force values and conditions into the instrument cluster. The results of these tests can be used to diagnose problems in the instrument cluster such as faulty Gauges and switches. Faults within other components can be identified after using Tech 2 to confirm correct operation of the instruments. For example, if there was a reported fault with the speedometer Gauge and Tech 2 diagnosed the Gauge as working correctly, then the fault would lie in the powertrain control module (PCM) or in the harness from the speed sensor to the PCM, both of which would then require further testing.