For 1990-2009 cars

Refer to

#### Power, Ground, CPP, AT, and Cruise Control Brake Switch

Engine Controls Components
Powertrain Control Module Description
Automatic Transaxle
Cruise Control Module, and VSS
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Power Distribution Schematics
Power Distribution Schematics
Cruise Control Schematics
in Engine Controls Schematics.

### Circuit Description

A Class 2 serial data communications system is used on this vehicle in order to allow various modules to communicate and share information with each other.

All modules on the Class 2 serial data line send out a periodic identifier message.

If the PCM does not receive an identifier message from a module, the PCM assumes that there is a loss of communication and a DTC is stored. A DTC P1626 will set after the engine has been started and there is a lost of communication between the PCM and the body control module (BCM). Since DTC P1626 is set after the engine has been started, the theft protection is bypassed at key-on. The vehicle will start, but as long as DTC P1626 is set there is no theft protection.

### Conditions for Running the DTC

• | The ignition is ON.

• | The system voltage is between 11 and 16 volts.

### Conditions for Setting the DTC

The PCM has lost communication with the body control module (BCM) after the PCM received a theft passed message from the BCM.

### Action Taken When the DTC Sets

• | The PCM will record operating conditions at the time the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers.

• | A history DTC stores.

### Conditions for Clearing the MIL/DTC

• | A history DTC will clear after 40 consecutive warm up cycles without a fault.

• | Use a scan tool can clear the DTCs.

### Diagnostic Aids

Attempting to start the vehicle by bypassing the Passlock ll system or by substituting parts without performing the password learn procedure may set a DTC P1631 and a P1632.

If no password is received, a DTC U1064 and P1632 may be set.

An intermittent may be caused by the following conditions:

• | Poor electrical terminal connection

• | Broken wire inside the insulation

Thoroughly inspect any suspected circuitry for the following items:

• | Backed out terminals or improper mating

• | Improperly formed or damaged terminals

• | Poor terminal to wiring connections

• | Physical damage to the wiring harness

• | Corrosion

### Test Description

The number below refers to the step number on the diagnostic table.

1. The replacement PCM must be programmed and the Crankshaft Position System Variation Learn procedure must be performed.

#### DTC P1626 - No Password Received from Body Control Module (BCM)

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Use a scan tool in order to determine if DTC U1064 is also set. Is DTC U1064 also set? | -- | Go to DTC U1001-U1254 Loss of XXX Communications in Data Communications | Go to Step 3
3 | Use a scan tool in order to determine if any body control module (BCM) DTCs are set. Are there any BCM DTCs set? | -- | Go to Diagnostic System Check - Body Control System in Body Control System | Go to Step 4
4 | Use a scan tool in order to determine if the BCM password is valid. Is the password valid? | -- | Go to Step 5 | Go to Diagnostic System Check - Body Control System in Body Control System
5 | Perform the Password Learn Procedure. Refer to Password Learn . Did you complete the Password Learn Procedure? | -- | Go to Step 8 | Go to Step 6
6 |

1. Inspect the PCM and the BCM connectors for faulty connections. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

7 | Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the repair? | -- | Go to Step 8 | --
8 |

1. Use a scan tool to clear 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