P1397

DTC P1397: WSSD Rough Road - Serial Data Fault

Wiring Diagram:

Circuit Description
The Engine Control Module (ECM) determines linear wheel speed excessive variation. The wheel speed variation test detects at least one missing edge from the wheel speed sensor signal.

Conditions for Setting the DTC
- The wheel speed variation test detects a failed wheel speed sensor under power conditions.
- No relevant DTCs are set.
- Coolant temperature is greater than or equal to 60 °C (140 °F).
- Vehicle voltage is between 11 and 16 V.
- Engine run time is greater than 10 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- The ECM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- A history Diagnostic Trouble Code (DTC) will clear after 40 consecutive warm up cycles without a fault.
- The DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for more than 10 seconds.

Diagnostic Aids
Check for the following conditions:
- Poor connection at the ECM - Inspect the harness connections for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connection.
- Damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, observe the G sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

An open signal circuit of open PWM serial data line between the ECM and the EBCM will be the cause of this DTC.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred.
The information is then stored on the scan tool for later reference.
2. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM reprogramming.

Step 1-8:

Troubleshooting