GM Service Manual Online
For 1990-2009 cars only

Object Number: 313527  Size: MF
Instrument Cluster and HUD Components
Cell 81: Driver Information and Head Up Display

Circuit Description

When you press the ENG/MET switch, circuit 1325 grounds. The instrument cluster detects the ground on terminal B10. The unit of measurement displayed on the instrument cluster changes.

Conditions for Setting the DTC

DTC B1521 sets under the following conditions:

    • The ignition is in RUN.
    • The ENG/MET switch is stuck or shorted to ground for greater than 60 seconds.

Action Taken When the DTC Sets

When DTC B1521 sets, the following actions may occur:

    • The instrument cluster disables the function of the ENG/MET switch for the remainder of that ignition cycle.
    • The DTC is set as a history DTC.
    • The instrument cluster displays the units displayed when the condition was detected.

Diagnostic Aids

Test for a binding, sticking or broken ENG/MET switch. If the ENG/MET switch is OK, clear the DTC. Perform the System Check. If the DTC is set current again, refer to DTC B1521 English/Metric Switch Stuck/Shorted To Ground diagnostic table.

Step

Action

Value(s)

Yes

No

1

  1. Connect a scan tool.
  2. Clear the DTC.
  3. Turn the ignition switch to OFF.
  4. Disconnect the switch.
  5. Turn the ignition switch to RUN.
  6. Wait for 60 seconds.
  7. Use a scan tool in order to test for DTC B1521

Is the DTC present?

--

Go to Step 2

Go to Step 3

2

Repair the short to ground in CKT 1816.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

--

3

Test the resistance between terminal E and terminal H (2 button switch) or between terminal E and terminal H (5 button switch).

Is the resistance less than the specified value?

5ohms

Go to Step 4

Go to Detecting Electrical Intermittent Cell 4

4

Replace the switch.

Is the repair complete?

--

Go to Diagnostic System Check - Instrument Cluster

--