GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Firebird 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0236

Circuit Description

The RPM signal circuit provides the EBCM with an indication of engine RPM to help determine TCS control methods and rates when a TCS event takes place.

Conditions for Setting the DTC

The EBCM does not receive an RPM input signal after 1 second, after the engine has been started.

Action Taken When the DTC Sets
    • A malfunction DTC is stored.
    • The TCS indicator is turned on.
    • The TCS is disabled. ABS remains functional.

Conditions for Clearing the DTC
    • The condition for DTC is no longer present and the scan tool Clear DTCs function is used.
    • 100 drive cycles have passed with no DTCs detected.

Diagnostic Aids

Perform a thorough inspection of the wiring. Perform a thorough inspection of the connectors. Failure to carefully and fully inspect the wiring and the connectors may result in misdiagnosis. Misdiagnosis causes part replacement with reappearance of the malfunction.

Test Description

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

  1. If the instrument panel tachometer is working properly, the cause of the malfunction is most likely between S120 and the EBCM, or the EBCM itself.

    2.

  2. At this point, the PCM is likely causing the malfunction. Refer to the appropriate OBD system check.

DTC C0236 RPM Signal Circuit Malfunction

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Start the engine.
  2. Vary the engine RPM with the throttle while observing the I/P tachometer.

Does the I/P tachometer work properly as the engine RPM changes?

--

Go to Step 3

Go to Step 4

3
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the PCM connector C2 from the PCM.
  3. Disconnect the EBCM connector C1 from the EBCM.
  4. Install the J 39700 Universal Breakout Box with the J 39700-530 Cable Adapter to the EBCM harness only.
  5. Use a J 39200 DMM to measure the resistance between the PCM harness connector C2 terminal 10 and the J 39700 Universal Breakout Box terminal 11.

Is the resistance within the specified range?

0-5 ohms

Go to Step 9

Go to Step 11

4
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the PCM connector C2 from the PCM.
  3. Disconnect the EBCM connector C1 from the EBCM.
  4. Install the J 39700 Universal Breakout Box with the J 39700-530 Cable Adapter to the EBCM harness only.
  5. Use a J 39200 DMM to measure the resistance between the PCM harness connector C2 terminal 10 and the J 39700 Universal Breakout Box terminal 11.

Is the resistance within the specified range?

0-5 ohms

Go to Step 5

Go to Step 12

5

Use a J 39200 DMM to measure the resistance between the J 39700 Universal Breakout Box terminal 11 and terminal 15.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 6

Go to Step 13

6
  1. Turn the ignition switch to the RUN position
  2. Use a J 39200 DMM to measure the voltage between the J 39700 Universal Breakout Box terminal 11 and terminal 15.

Is the voltage within the specified range?

0-2 V

Go to Step 7

Go to Step 14

7
  1. Inspect the PCM connector for the following:
    2. • Inspect for damage.
    • Inspect for poor terminal contact.
    • Inspect for corrosion.
  2. Inspect the EBCM connector for the following:
    3. • Inspect for damage.
    • Inspect for poor terminal contact.
    • Inspect for corrosion.
  3. Ensure both the PCM connector and the EBCM connector are properly retained when connected.

Are the following signs present on either connector:

    • Is poor terminal contact present?
    • Is corrosion present?
    • Is damaged terminals present?

--

Go to Step 15

Go to Step 8

8
  1. Reconnect all the connectors.
  2. Using the scan tool clear the DTC.
  3. Disconnect the scan tool from the DLC.
  4. Start the engine.

Did DTC C0236 reset?

--

Go to Step 10

Go to Diagnostic System Check - ABS

9

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

10

Suspect PCM. Refer to Powertrain Control Module Replacement in Engine Controls.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

11

Repair an open in CKT 121 between S120 and the EBCM harness connector terminal 11. Refer to Wiring Repairs .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

12

Repair an open in CKT 121 between S120 and the PCM harness connector C2 terminal 10. Refer to Wiring Repairs .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

13

Repair a short to ground in CKT 121. Refer to Wiring Repairs .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

14

Repair a short to voltage in CKT 121. Refer to Wiring Repairs .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

15

Replace all the terminals or replace the connectors that exhibit signs of the following:

    • That exhibit signs of poor terminal contact.
    • That exhibit signs of corrosion.
    • That exhibit signs of damaged terminals.

Refer to Connector Repairs in Electrical Diagnosis.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--