GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument panel module (IPM) is the power mode master and the remote control door lock receiver (RCDLR) is the backup power mode master. Both modules receive information regarding ignition mode switch position from the ignition mode switch. IPM receives ignition mode switch position data through the IPM ignition mode data signal circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1385 Device Ignition START Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom

DTC Symptom Descriptor

01

Short to Battery

59

Component Protection Time-Out

Conditions for Running the DTC

Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.

Conditions for Setting the DTC

B1385 01

The IPM sets the code if it detects a short to battery on ignition mode switch signal circuit.

B1385 59

The IPM sets the code if it detects that the START contact of the ignition mode switch is closed for more than 30 seconds.

Action Taken When the DTC Sets

B1385 01

The IPM does not react to switch inputs until condition is cleared.

B1385 59

The IPM does not react to switch inputs of equal or lower priority until condition is cleared.

Conditions for Clearing the DTC

    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids

The following can cause the code to set as history:

    • An intermittent short to battery on ignition mode switch signal circuit.
    • An intermittent problem of the ignition mode switch
    • The START button of the ignition mode switch was pressed for more than 30 seconds.

Step

Action

Values

Yes

No

Schematic Reference: Power Distribution Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Is the DTC B1385 set as current?

--

Go to Step 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the ignition mode switch.
  3. With a DMM measure the resistance between cavities E and F at the ignition mode switch. Press and release the START button during the measurement.

Do the values measured toggle from one to the other specified values?

0/450 Ω

Go to Step 6

Go to Step 4

4

Inspect for poor connections and terminal tension at the harness connector of the ignition mode switch. Refer to Testing for Intermittent Conditions and Poor Connections .

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

5

Replace the ignition mode switch. Refer to Ignition and Start Switch Replacement .

Did you complete the replacement?

--

Go to Step 9

--

6

  1. Disconnect the instrument panel module (IPM).
  2. Test the IPM ignition mode data signal circuit for a short to battery. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

Inspect for poor connections and terminal tension at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections .

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

8

Replace the IPM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 9

--

9

  1. Reconnect all components.
  2. Use the scan tool in order to clear the DTC.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 3

System OK