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Home >> Cadillac >> 2003 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 633 (Antilock Brake System, Traction Control System & Stability Control System) >> Diagnostic Information and Procedures >> DTC C0241 or P0856: Powertrain Control Module (PCM) Indicated >> Test Description
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Test Description

WARNING: This page is about a different car, the 2004 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  Use the scan tool in order to determine if the requested torque signal has a valid duty cycle.
  2. 3:  Measure the requested torque signal in order to determine if the signal has a valid duty cycle.
  3. 4:  Measure the requested torque signal in order to determine if the signal has a valid frequency.
  4. 10:  This vehicle is equipped with a ECM which uses an electrically erasable programmable read only memory (EEPROM). When replacing the ECM, the replacement ECM must be programmed.
DTC C0241 or P0856

Step Action Value(s) Yes No
Schematic Reference:  ABS Schematics  
Connector End View Reference: ABS Connector End Views ,Engine Controls Connector End Views in Engine Controls - 3.6L, or Engine Controls Connector End Views in Engine Controls - 2.6L and 3.2L
1 Did you perform the ABS Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - ABS 
2 
  1. Install a scan tool.
  2. Start the engine.
  3. With a scan tool, observe the Torque Request Signal parameter in the Powertrain Control Module data list.
Does the scan display less than the specified value?		 100% Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Install the J 39700  universal breakout box using the J 39700-300  cable adapter to the EBCM harness connector and the EBCM connector. See Special Tools and Equipment .
  4. Start the engine.
  5. Measure the DC duty cycle between the requested torque signal circuit and a good ground.
Is the duty cycle within the specified range?		 5-95% Go to Step 4  Go to Step 5 
4  Measure the DC frequency between the requested torque signal circuit and a good ground.
Does the frequency measure within the specified range?		 121-134 Hz Go to Step 7  Go to Step 5 
5
  1. Turn OFF the ignition.
  2. Disconnect the J 39700-300  cable adapter from the EBCM connector. See Special Tools and Equipment .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the requested torque signal circuit to a good ground.
Does the voltage measure within the specified range?		 4-6 V Go to Step 9  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM) harness connector.
  3. Test the requested torque signal circuit for the following conditions:
    • A short to voltage
    • A short to ground
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
7
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM) harness connector.
  3. Test the requested torque signal circuit for the following conditions:
    • An open
    • A high resistance
Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 - Go to Step 12  Go to Step 8 
8 Inspect for poor connections the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 10 
9 Inspect for poor connections the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
10 
IMPORTANT: The replacement ECM must be programmed.
Replace the ECM. Refer to Engine Control Module (ECM) Replacement in Engine Controls - 3.6L, or Engine Control Module (ECM) Replacement in Engine Controls - 2.6L and 3.2L.Did you complete the repair?		 - Go to Step 12  -
11 Replace the EBCM. Refer to Electronic Brake Control Module Replacement (CTS)  or Electronic Brake Control Module Replacement (CTS-V) .
Did you complete the repair?		 - Go to Step 12  -
12
  1. Use the scan tool in order to clear the 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
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