DTC C0040 RF Wheel Speed Circuit Malfunction. Chevrolet Prizm 1998

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1998 🢒 Prizm 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0040 RF Wheel Speed Circuit Malfunction

ABS Components
Antilock Brake System Schematics

Circuit Description

The Electronic Brake Control Module (EBCM) receives a voltage signal from the right front wheel speed sensor through terminals 19 and 20. As a toothed reluctor wheel ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a small AC voltage signal. This signal's frequency is proportional to the wheel speed.

Conditions for Setting the DTC

•	DTC C0040 will set when the EBCM detects an open, a short to voltage, or a short to ground in CKT 833 or CKT 872.

•	DTC C0040 can be set anytime.

Action Taken When the DTC Sets

•	A malfunction DTC stores.

•	The ABS disables.

•	The ABS warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.

Diagnostic Aids

Inspect the following items when diagnosing this part of the Antilock Brake System (ABS):

•	Faulty electrical circuits between the right front wheel speed sensor and the EBCM. These faults include the following:

-	Open and or high resistance

-	Short to voltage

-	Short to ground

•	Faulty right front wheel speed sensor (out of range resistance).

An intermittent malfunction is most likely caused by a poor connection rubbed thorough wire insulation, or by a wire that is broken inside the insulation.

If the customer comments reflect that the ABS indicator lamp is ON only during humid conditions (rain, snow, vehicle wash), thoroughly inspect the right front wheel speed sensor circuitry for signs of water intrusion.

Inspect the harness connectors for the following conditions:

•	Backed-out terminals

•	Improper mating

•	Broken locks

•	Improperly formed or damaged terminals

•	Poor terminal to wiring connections

•	Physical damage to the wiring harness

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

The Diagnostic System Check must be the starting point for any ABS related diagnosis.

Tests for wheel speed sensor internal resistance for proper values.

Tests for wheel speed sensor circuits shorted together.

Tests for a short to ground in CKT 833.

Tests for a short to ground in CKT 872.

Tests for a short to voltage in CKT 833.

Tests for a short to voltage in CKT 872.

Tests for an open or high resistance in CKT 833.

Tests for an open or high resistance in CKT 872.

Tests for a poor connections at electrical connectors.

Determines whether the condition is intermittent and not due to a faulty EBCM.

Important: Wheel speed sensor resistance increases with an increase in sensor temperature.

When measuring for a short to ground in a wheel speed sensor wiring circuit manually switch to J 39200 (Digital Multimeter) to the Meg-Ohms range. This will ensure a high resistance short to ground can be found. See J 39200 owners manual.

Step

Action

Value(s)

Yes

Was the Diagnostic System Check performed?

Go to Step 2

Go to Diagnostic System Check

Remove the right front wheel. Refer to Tire and Wheel Removal and Installation .
Disconnect the right front wheel speed sensor electrical connector.
Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminal A and terminal B (sensor side).

Is the resistance within the range specified in the Value(s) column?

1120-2520 ohms

Go to Step 3

Go to Step 12

Disconnect the Electronic Brake Control Module (EBCM) electrical connector.
Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminal A and terminal B (harness side).

Is the resistance equal to the value specified in the Value(s) column?

(Infinite)

Go to Step 4

Go to Step 13

Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminals A (harness side) and ground.

Is the resistance within the range specified in the Value(s) column?

(Infinite)

Go to Step 5

Go to Step 14

Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminal B (harness side) and ground.

Is the resistance equal to the value specified in the Value(s) column?

(Infinite)

Go to Step 6

Go to Step 15

Turn the ignition switch to the ON position.
Use J 39200 DMM in order to measure the voltage between the right front wheel speed sensor connector terminal A (harness side) and ground.

Is the voltage within the range specified in the Value(s) column?

0-1 V

Go to Step 7

Go to Step 16

Use J 39200 DMM in order to measure the voltage between the right front wheel speed sensor connector terminal B (harness side) and the ground.

Is the voltage within the range specified in the Value(s) column?

0-1 V

Go to Step 8

Go to Step 17

Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminal A (harness side) and the EBCM electrical connector terminal 19 (harness side).

Is the resistance less than or equal to the value specified in the Value(s) column?

2 ohms

Go to Step 9

Go to Step 18

Use J 39200 DMM in order to measure the resistance between the right front wheel speed sensor connector terminal B (harness side) and the EBCM electrical connector terminal 20 (harness side).

Is the resistance within the range specified in the Value(s) column?

0-2 ohms

Go to Step 10

Go to Step 19

Inspect The EBCM electrical and the right front wheel speed sensor connector for the following conditions:

•	Poor terminal contact

•

Corrosion

•

Damage

Repair as necessary. Refer to Wheel Speed Sensor Replacement .

Is the repair complete?

Go to Step 11

Turn the ignition switch to the LOCK position.
Reconnect the right front wheel speed sensor electrical connector.
Reconnect the EBCM electrical connector.
Turn the ignition switch to the ON position.
Connect a scan tool to the Data Link Connector (DLC).
Select Diagnostic Trouble Codes (DTC) on the scan tool.
Select DTC Information on the scan tool.
Select Current DTC on the scan tool.

Is DTC C0040 set as a Current DTC?

Go to Step 21

Go to Step 20

Replace the right front wheel speed sensor. Refer to Wheel Speed Sensor Replacement .

Is the repair complete?

Go to Diagnostic System Check

Repair the short between CKT 833 and CKT 872. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the short to ground in CKT 833. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the short to ground in CKT 872. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the short to voltage in CKT 833. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the short to voltage in CKT 872. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the open or high resistance in CKT 833. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

Repair the open or high resistance in CKT 872. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Diagnostic System Check

A malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC.

Is the action complete?

Go to Diagnostic System Check

Test the electrical harness between the EBCM and the right front wheel speed sensor for a possible short to ground, short to voltage, or open in CKT 833 and/or CKT 872.
Inspect the EBCM electrical connector for poor terminal contact.
Repair wiring as necessary.
If wiring is OK, replace the EBCM. Refer to Brake Pressure Modulator Valve Assembly Replacement .

Is the action complete?

Go to Diagnostic System Check