Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Procedure
- EB1 CHECK FOR DTCS
Is DTC P04D7 present?
Yes No GO to EB2. RETURN to SYMPTOM CHARTS for further direction. - EB2 CHECK THE ENGINE BRAKE SWITCH OPERATION
- Ignition ON, engine OFF.
- Access the PCM and monitor the EXHAUST_BRK (MODE) PID.
- Press the engine brake switch.
Does the EXHAUST_BRK PID state change when the engine brake switch is pressed?
Yes No Unable to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. Wiggle the harness attempting to recreate the concern. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.GO to EB3. - EB3 CHECK FOR CIRCUIT VOLTAGE
- Ignition OFF.
- Engine Brake Switch connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) Engine Brake Switch Connector, Harness Side (-) VPWR - Pin 1 Ground Is the voltage greater than 10.5 V?
Yes No GO to EB4. REPAIR the open circuit. Clear the PCM DTCs.
REPEAT the self-test. - EB4 CHECK THE ENGINE BRAKE SWITCH FOR CORRECT OPERATION
- Ignition OFF.
- Press and release the engine brake switch while measuring the resistance.
- Measure the resistance between:
(+) Engine Brake Switch Connector, Component Side (-) Engine Brake Switch Connector, Component Side VPWR - Pin 1 EBIS - Pin 4 Is the resistance greater than 10, 000 ohms with the engine brake switch released and less than 5 ohms with the engine brake switch pressed?
Yes No GO to EB5. INSTALL a new Engine Brake switch. REFER to the appropriate Anti-Lock Brake System (ABS) and Stability Control article.
Clear the PCM DTCs. REPEAT the self-test. - EB5 CHECK THE EBIS CIRCUIT FOR AN OPEN
- Ignition OFF.
- PCM-B connector disconnected.
- Measure the resistance between:
(+) PCM-B Connector, Harness Side (-) Engine Brake Switch Connector, Harness Side EBIS - Pin 6 EBIS - Pin 4 Is the resistance less than 5 ohms?
Yes No GO to EB6. REPAIR the open circuit. Clear the PCM DTCs.
REPEAT the self-test. - EB6 CHECK THE EBIS CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between:
(+) Engine Brake Switch Connector, Harness Side (-) EBIS - Pin 4 Ground Is the resistance greater than 10K ohms?
Yes No GO to EB7. REPAIR the short circuit. Clear the PCM DTCs.
REPEAT the self-test. - EB7 CHECK THE EBIS CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) Engine Brake Switch Connector, Harness Side (-) EBIS - Pin 4 Ground Is any voltage present?
Yes No REPAIR the short circuit. Clear the PCM DTCs.
REPEAT the self-test.GO to EB8. - EB8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test.
- Verify the concern is still present.
Is the concern still present?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . The system is operating correctly at this time.
The concern may have been caused by a loose or corroded connector.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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