For 1990-2009 cars

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

2. Tests for an open in the Passlock™ sensor signal circuit, which may not set a DTC (B2958) under certain conditions.

3. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

4. The presence of DTC P0601, P0602, or P0604 indicates an internal fault in the PCM.

5. The presence of DTC B1000 indicates an internal module fault.

6. The presence of DTC P0562, P0563, or P0621 indicates a low or high voltage condition.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Theft Deterrent System Schematics
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up
2 |

1. Turn ON the ignition, with the engine OFF.
2. Attempt to establish communication with the following control modules:

• | The powertrain control module (PCM)

• | The body control module (BCM)

• | The instrument panel cluster (IPC)

Does the scan tool communicate with the all the listed control modules?

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Device

3 | Select the display DTCs function on the scan tool for the following control modules:

• | The PCM

• | The BCM

• | The IPC

Does the scan tool display any DTCs?

Go to Step 5

Go to Step 4

4 |

1. Momentarily rotate the ignition switch to CRANK. Do not start the vehicle.
2. Release the ignition switch to ON.
3. With a scan tool, observe the Passlock Code in the Body Control Module Security Data list.

Does the scan tool display OPEN?

Go to DTC B2958

Go to Symptoms - Theft Deterrent

5 | Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device | Go to Step 6
6 | Does the scan tool display DTC P0601, P0602 or P0604? | Go to Diagnostic Trouble Code (DTC) List for the 2.2L (L61) engine or Diagnostic Trouble Code (DTC) List for the - 3.0L (L81) engine | Go to Step 7
7 | Does the scan tool display DTC B1000? | Go to DTC B1000 | Go to Step 8
8 | Does the scan tool display DTC P0562, P0563, P0621, or P0622? | Go to Diagnostic Trouble Code (DTC) List | Go to Diagnostic Trouble Code (DTC) List