P1396

DTC P1396 or P1397

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC P1396
- Wheel Speed Sensor Circuit w/o ABS

DTC P1397
- Wheel Speed Sensor Circuit w/ABS

Circuit/System Description

The engine control module (ECM) determines engine misfire by detecting variations in crankshaft speed. Crankshaft speed variations can also occur when a vehicle is operating over a rough road. The wheel speed sensor produces an alternating current (AC) voltage that increases with wheel speed. The ECM receives a rough road signal from an electronic brake control module (EBCM), if equipped with the anti-lock brake system (ABS). The ABS can determine if the vehicle is on a rough road surface based on the signal from each wheel speed sensor. On vehicles with Non-ABS, a rough road signal is sent from a wheel speed sensor located at the left front wheel to the ECM. The ECM can determine if the vehicle is on a rough road surface based on the signal from the wheel speed sensor. When the ECM detects a rough road condition, misfire diagnostics will be disabled.

Conditions for Running the DTC

* DTCs P0106, P0107, P0108, P0115, P0116, P0117, P0118, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0217, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0351, P0352, P0402, P0404, P0405, P0406, P042E and P0488 are not set.
* The engine run time is greater than 10 seconds.
* The engine coolant temperature (ECT) is greater than or equal to 60°C (140°F).
* The ignition voltage is between 11-16 volts.
* The DTCs run continuously once the above condition is met.

Conditions for Setting the DTC

P1396

The ECM detects an invalid rough road signal from the wheel speed sensor.

P1397

The ECM detects an invalid rough road signal from the EBCM.

Action Taken When the DTC Sets

DTC P1396 and P1397 are Type C DTCs

Conditions for Clearing the DTC

DTC P1396 and P1397 are Type C DTCs

Circuit/System Verification

1. Engine running, DTC P1396 or P1397 should not set.
2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

Circuit/System Testing

Important: If the ABS lamp is illuminated, the ABS system must be diagnosed prior to using this diagnostic procedure. Refer to Diagnostic System Check - Vehicle. Initial Inspection and Diagnostic Overview

1. Ignition OFF, disconnect the harness connector of the wheel speed sensor or the EBCM, if equipped with ABS.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit and ground.

• If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts on the signal circuit.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.

• If less than the specified range, test the signal circuit for a short to ground or an open. If the circuit/connections test normal, replace the ECM.

4. If all circuits/connections test normal, test or replace the wheel speed sensor or EBCM, if equipped with ABS.

Component Testing

Important: This procedure is for vehicle without ABS. If the wheel speed sensor harness is damaged in any way, DO NOT repair the harness.

1. Ignition OFF, disconnect the harness connector of the wheel speed sensor.

Notice: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.

2. Raise and support the drive wheels.
3. Engine running, place the transmission into 2nd gear or drive for an automatic.
4. Test for 70 mV AC between the rough road signal circuit and low reference circuit.

• If less than 70 mV AC, replace the wheel speed sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Programming and Relearning for ECM or EBCM setup, and programming
Programming and Relearning