GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Malibu 🢒 DTC 🢒 DTC U2000-U2007

Circuit Description

The IPC and the body control module BCM communicate over an exclusive serial peripheral interface, SPI. The BCM and the IPC are the only two modules that use the SPI serial data circuit implemented on the vehicle. The IPC receives information from the BCM over the SPI serial data "A" circuit. The BCM transmits information to the IPC in order to control various indicators, the engine coolant temperature gage, speedometer, Tachometer and the fuel gage. The BCM receives data from the IPC's over the SPI serial data "B" circuit. The IPC transmits information such as tachometer active status, speedometer active status, and invalid data received messages. The BCM synchronizes the data signals by toggling the SPI serial data clock circuit to ground. The IPC can not hold any Class 2 DTC's, all Class 2 DTC setting and holding is handled in the BCM.

Conditions for Setting the DTC

The ignition switch is in the Run position and the battery is properly charged.

Conditions For Setting the DTC

U2000

The IPC determines that the BCM transmitted data to the IPC that was invalid for greater than 12 seconds. The IPC sends a message to the BCM via the IPC's SPI serial data "B" circuit, indicating that invalid data was received. The BCM holds the DTC, not the IPC.

U2001

U2001 is set, in the BCM, when the BCM determines that the IPC transmitted data to the BCM that was invalid for greater than 5 seconds.

U2002

U2002 is set, in the BCM, when it detects that the SPI serial data "B" circuit, is less than 1.2 v for greater than 5 seconds.

U2003

U2003 is set, in the BCM, when it detects that the SPI serial data "B" circuit, is greater than 4.5 v for greater than 5 seconds.

U2004

U2004 is set, in the BCM, when it detects that the SPI serial data "A" circuit, is less than 1.2 v for greater than 5 seconds.

U2005

U2005 is set, in the BCM, when it detects that the SPI serial data "A" circuit, is greater than 4.5 v for greater than 5 seconds.

U2006

The BCM is the generator of the SPI serial data synchronizing Clock signal. U2006 is set, in the BCM, when the Clock circuit is less than 1.2 v for greater than 5 seconds.

U2007

The BCM is the generator of the SPI serial data synchronizing Clock signal. U2007 is set, in the BCM, when the Clock circuit, is greater than 4.5 v for greater than 5 seconds.

Action Taken When the DTC Sets

U2000, U2004, U2005, U2006, U2007

The IPC takes the following default action:

    • The fuel gage displays empty.
    • The engine coolant temperature gage displays 100°F.
    • The VTD indicator, ABS indicator, and SERVICE VEHICLE SOON indicator illuminate.

Conditions for Clearing the DTC
    • A current DTC clears on the next malfunction free cycle.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids
    • A low vehicle battery voltage can cause some of the DTC's to set. Make sure that the vehicle battery is fully charged.
    • An open B+ supply to the BCM or the IPC could cause some of the DTC's to set. Check the modules supply fuses.

Test Description

  1. This step is a preliminary test to try to identify if a malfunction is present in the SPI serial data "A" circuit .

    2.

  2. This step is a preliminary test to try to identify in which area of the circuit the malfunction could be present.

    3.

  3. This step is a preliminary test to try to identify if a malfunction is present in the SPI serial data "B" circuit .

    4.

  4. This step is a preliminary test to try to identify in which area of the SPI serial data Clock circuit the malfunction could be present.

    5.

  5. This multiple test is for checking the condition of the wiring media of the SPI serial data "A" circuit and the harness connectors used between the two modules.

    6.

  6. This multiple test is for checking the condition of the wiring media of the SPI serial data "B" circuit and the harness connectors used between the two modules.

    7.

  7. This multiple test is for checking the condition of the wiring media and the harness connectors used between the two modules in the SPI serial data Clock circuit.

    8.

  8. This step instructs, to replace the IPC. Because of the necessity of higher order electronic test equipment to fully analyze the SPI serial data circuit, it may also be necessary to also replace the BCM.

    9.

  9. This step instructs, to replace the BCM. Because of the necessity of higher order electronic test equipment to fully analyze the SPI serial data circuit, it may also be necessary to also replace the IPC.

Step

Action

Value(s)

Yes

No

Schematic Reference: Body Control System Schematics

1

Did you perform the Instrument Cluster Diagnostic System Check?

 

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console for the proper procedure.

2

Does the scan tool display DTC's U2000 or U2004?

 

Go to Step 6

Go to Step 3

3

Does the scan tool display DTC U2005?

 

Go to Step 7

Go to Step 4

4

Does the scan tool display DTC's U2001, U2002 or U2003?

 

Go to Step 10

Go to Step 5

5

Does the scan tool display DTC U2006 or U2007?

 

Go to Step 12

Go to Step 19

6

  1. Turn OFF the ignition.
  2. Disconnect the BCM connector containing the SPI serial data "A" circuit.
  3. Turn ON the ignition with the engine OFF.
  4. Measure the voltage from the BCM harness connectors SPI serial data "A" circuit terminal, to a good ground.

Does the voltage measure greater than the specified value?

9.0 V

Go to Step 9

Go to Step 14

7
  1. Turn OFF the ignition.
  2. Disconnect the BCM connector containing the SPI serial data "A" circuit circuit.
  3. Turn ON the ignition with the engine OFF.
  4. Measure the voltage from the BCM harness connectors SPI serial data "A" circuit terminal, to a good ground.

Refer to Body Control System Schematics and Measuring Voltage for the circuit ID's and the proper procedures.

Does the voltage measure greater than the specified value?

9.0 V

Go to Step 8

Go to Step 14

8
  1. Remove the connector from the IPC that contains the SPI serial data "A" circuit.
  2. Test the SPI serial data "A" circuit terminal in the harness connector of the BCM, for a short to B+.

Refer to Body Control System Schematics and Testing for a Short to Voltage for the circuit ID's and the proper procedures.

Did you find and correct the condition?

 

Go to Step 19

Go to Step 17

9
  1. Remove the connector from the IPC that contains the SPI serial data "A" circuit .
  2. Test the SPI serial data "A" circuit terminal in the harness connector of the BCM, for a short to B+.

Refer to Body Control System Schematics and Testing for a Short to Voltage for the circuit ID's and the proper procedures.

Did you find and correct the condition?

9.0 V

Go to Step 19

Go to Step 18

10

  1. Turn OFF the ignition.
  2. Disconnect the IPC connector containing the SPI serial data "B" circuit.
  3. Turn ON the ignition with the engine OFF.
  4. Measure the voltage from the IPC harness connectors SPI serial data "B" circuit terminal, to a good ground.

Refer to Body Control System Schematics and Testing for a Short to Voltage for the circuit ID's and the proper procedures.

Does the voltage measure greater than the specified value?

9.0 V

Go to Step 11

Go to Step 15

11
  1. Remove the connector from the BCM that contains the SPI serial data "B" circuit .
  2. Test the SPI serial data "B" circuit terminal in the harness connector of the IPC, for a short to B+.

Refer to Body Control System Schematics and Testing for a Short to Voltage for the circuit ID's and the proper procedures.

Did you find and correct the condition?

 

Go to Step 19

Go to Step 17

12

  1. Turn OFF the ignition.
  2. Disconnect the BCM connector containing the SPI serial data Clock circuit.
  3. Turn ON the ignition with the engine OFF.
  4. Measure the voltage from the BCM harness connectors SPI serial data Clock terminal, to a good ground.

Refer to Body Control System Schematics and Measuring Voltage for the circuit ID's and the proper procedures.

Does the voltage measure greater than the specified value?

9.0 V

Go to Step 13

Go to Step 16

13
  1. Remove the connector from the IPC that contains the SPI serial data Clock circuit.
  2. Test the SPI serial data Clock circuit terminal in the harness connector of the BCM, for a short to B+.

Refer to Body Control System Schematics and Testing for a Short to Voltage for the circuit ID's and the proper procedures.

Did you find and correct the condition?

 

Go to Step 19

Go to Step 17

14

  1. Remove the connector from the IPC that contains the SPI serial data "A" circuit .
  2. Test the SPI serial data "A" circuit terminal in the harness connector of the IPC for a short to voltage, short to ground or high resistance.
  3. Inspect for poor connections at the IPC and BCM harness connector terminals containing the applicable SPI serial data circuit.

Refer to the following sections for the circuit ID's and the proper procedures.

    •  Circuit Testing

Did you find and correct the condition?

 

Go to Step 19

Go to Step 18

15

  1. Remove the connector from the BCM that contains the SPI serial data "B" circuit.
  2. Test the SPI serial data "B" circuit terminal in the harness connector of the BCM for a short to voltage, short to ground or high resistance.
  3. Inspect for poor connections at the BCM and IPC harness connector terminals containing the applicable SPI serial data circuit.

Refer to the following sections for the circuit ID's and the proper procedures.

    •  Circuit Testing

Did you find and correct the condition?

 

Go to Step 19

Go to Step 17

16

  1. Remove the connector from the IPC that contains the SPI serial data Clock circuit.
  2. Test the SPI serial data Clock circuit terminal in the harness connector of the BCM for a short to voltage, short to ground or high resistance.
  3. Inspect for poor connections at the IPC and BCM harness connector terminals containing the Clock SPI serial data circuit.

Refer to the following sections for the circuit ID's and the proper procedures.

    •  Circuit Testing

Did you find and correct the condition?

 

Go to Step 19

Go to Step 18

17

  1. Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console for the proper procedure.
  2. Reconnect all disconnected connectors.
  3. Install the scan tool.
  4. Turn ON the ignition with the engine OFF.
  5. Use the scan tool in order to clear the DTCs.
  6. Operate the vehicle within the Conditions for Running the DTC's as specified in the supporting text.

Does the DTC reset?

 

Go to Step 18

Go to Step 19

18

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

  1. Replace the BCM. Refer to Body Control Module Replacement for the proper procedure.
  2. Reconnect all disconnected connectors.
  3. Install the scan tool.
  4. Turn ON the ignition with the engine OFF.
  5. Use the scan tool in order to clear the DTCs.
  6. Operate the vehicle within the Conditions for Running the DTC's as specified in the supporting text.

Does the DTC reset?

 

Go to Step 17

Go to Step 19

19

Operate the vehicle within the Conditions for Running the DTC's as specified in the supporting text.

Does the DTC reset?

 

Go to Step 2

System OK