Engine Brake Control Fault
There’s a malfunction in the engine brake control system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine brake isn’t working as it should because of an issue in the system controlling it, like a faulty switch or a broken wire.
What the computer is actually seeing
The engine control unit (ECU) monitors signals from the engine brake module, looking for expected inputs when the brake is engaged. If it receives out-of-range signals or no signal at all, it flags this code.
What a healthy reading looks like
Expected voltage at the engine brake control switch should be around 0V (off) and 5V (on); resistance in wiring should be below 5 ohms.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the engine brake switch for proper operation: should show 0V when off and 5V when engaged. If not, replace the switch.
- 2Inspect wiring for damage, especially chafing or breaks. Repair as necessary.
- 3Examine connections for corrosion or loose terminals. Clean or replace connectors.
- 4Use a scan tool to check for related fault codes that might indicate further issues in the engine control module.
- 5Check for software updates or ECU faults if previous steps are clear.
Common causes
- Faulty engine brake switch
- Wiring issues in the engine brake circuit
- Faulty engine control module
- Corroded connectors
- Software issues in the ECU
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's generally safe to drive, but engine braking will be limited. Use caution when descending hills.
Will this issue come back if I clear the code?
It can if the underlying cause isn't fixed. If the switch or wiring is bad, the code will return.
Why do I see this code with SPN 1999?
Both codes are related to the engine brake system, indicating faults in the control mechanism.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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