GM Service Manual Online
For 1990-2009 cars only
Table 1: Normal Device Power Moding
Table 2: Code Setting Criteria (Fault) for Device Power Moding

Object Number: 603140  Size: MF

Circuit Description

Class 2 communications will not start until the vehicle systems ON power mode has been identified. Three discrete wires from the ignition switch contacts are monitored by the Instrument Cluster (IPC) in order to determine the present power mode (ignition switch position). The IPC communicates the system power mode to all class 2 modules on the class 2 serial data line.

Conditions for Running the DTC

The IPC must be powered.

Conditions for Setting the DTC

One of the three monitored ignition switch circuits has malfunctioned.

Action Taken When the DTC Sets

The IPC implements default actions for each ignition switch position when faults are detected.

Conditions for Clearing the DTC

The power moding malfunction must be corrected and then the code can be cleared by using the scan tool. The code also clears after 100 ignition cycles.

Normal Device Power Moding

Key Position

ACC

IGN 1

IGN 0

Engine Running

Power Mode

OFF

Inactive

Inactive

Inactive

No

OFF or RAP

ACC

Active

Inactive

Inactive

No

ACC

UNLOCK

Inactive

Inactive

Active

No

UNLOCK or RAP

CRANK

Inactive

Active

Active

No

CRANK

RUN

Active

Active

Active

No

RUN

RUN

Active

Active

Active

Yes

RUN

Code Setting Criteria (Fault) for Device Power Moding

ACC

IGN 1

IGN 0

Engine Running

Power Mode (Default)

Inactive

Active

Inactive

No

OFF or RAP

Inactive

Active

Inactive

Yes

RUN

Active

Active

Inactive

No

RUN

Active

Active

Inactive

Yes

RUN

Inactive

Active

Active

Yes

RUN (Fault is set only if this condition exists for more than 1 minute)

Active

Inactive

Inactive

Yes

RUN

Active

Inactive

Active

Yes

RUN

Step

Action

Value(s)

Yes

No

1

Did you perform the instrument cluster diagnostic system check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine Off.
  3. With a scan tool, observe the ignition switch input parameters in the IP input data list.

Do all of the ignition switch input parameters display on?

--

Go to Step 6

Go to Step 3

3

Test the ignition switch circuits that displayed inactive on the scan tool for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 4

4

Check for poor connections at the IP. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 5

5

Check for poor connections at the ignition switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

6

  1. Turn OFF the ignition.
  2. With a scan tool, observe the ignition switch input parameters.

Does the scan tool communicate and the ignition 1 parameter display active?

--

Go to Step 8

Go to Step 7

7

  1. Turn the ignition switch to the ACCY position.
  2. With a test lamp, probe the ignition switch input parameters. Refer to Circuit Testing in Wiring Systems.

Is the test lamp off for the ignition switch Ign 1 input and Ign 0 input parameters and on for the ACCY input parameter?

--

Go to Step 11

Go to Step 10

8

Test the Ignition switch circuit(s) that displayed Active in Step 6 for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

9

  1. Turn the ignition switch in the ACCY position.
  2. Probe the circuit, that displayed Active in Step 6, at the ignition switch with a test lamp that is connected to a good ground.

Did the test lamp illuminate?

--

Go to Step 10

Go to Step 11

10

Replace the ignition switch. Refer to Ignition Switch Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Did you complete the replacement?

--

Go to Step 12

--

11

Important: Perform the set up procedure for the replacement IPC.

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement and the set up procedure?

--

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Step 2