GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 CTS 🢒 Vehicle Control Systems 🢒 Computer/Integrating Systems 🢒 DTC B1390

Circuit Description

The dash integration module (DIM) has an internal battery voltage sense input and a reference voltage input. The DIM compares these 2 voltages via the 2 battery positive voltage circuits every 300 milliseconds.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1390 Device Voltage Reference Input Circuit

Conditions for Running the DTC

This DTC will run only if the DIM has battery positive voltage power and ground. This DTC will execute regardless of the source voltage.

Conditions for Setting the DTC

This code shall be set after 10 consecutive readings that the 2 battery positive voltages differ by 1 volt or greater.

Action Taken When the DTC Sets

All writes to the electronically erasable programmable read-only memory (EEPROM) will be suspended. Setting of all loss of communication and low/high voltage DTCs are suspended.

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.

Step

Action

Values

Yes

No

Schematic Reference: Body Control System Schematics

Connector End View Reference: Computer/Integrating Systems Connector End Views

1

Did you perform Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF the ignition.
  2. Disconnect the dash integration module (DIM).
  3. Turn ON the ignition, with the engine OFF.
  4. Measure and record the voltage from both battery positive voltage circuits of the DIM to both ground circuits of the DIM. Refer to Circuit Testing .
  5. Compare the 2 recorded DIM battery positive voltage circuit voltages.

Is the voltage difference less than the specified value?

1 V

Go to Step 5

Go to Step 3

3

Test both DIM battery positive voltage circuits for a high resistance or an open. Refer Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 4

4

Test both DIM ground circuits for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 5

5

Inspect for poor connections at the harness connector of the DIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

6

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

Did you complete the replacement?

--

Go to Step 7

--

7
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK