C1129 Engine Trouble Code
What is C1129?
With C1129, you may drive for several weeks with a malfunctioning MAF sensor, but expect decreased fuel economy and eventual stalling. Shop replacement costs $240–$400 depending on vehicle. The labour is straightforward, with most cost from the part itself.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C1129 |
C1129 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
C1129 Code Structure
Understanding what each digit means in the C1129 chassis trouble code:
| C | 1 | 1 | 2 | 9 |
|---|---|---|---|---|
| Chassis Code | Fuel And Air Metering | Fuel Rail/System Pressure — Too High | Turbocharger Boost Sensor A Circuit Low | Reverse Input Circuit |
How to Fix C1129
Diagnostic Steps:
Poor running symptoms align with MAP sensor malfunction. In some cases, a faulty MAP sensor will not trigger a code. The issue may represent separate wiring concerns requiring individual diagnosis.
Repair Solution:
Brake switch circuit concerns may involve open or shorted BPP circuits, damaged switches, or misadjustment. Verify stoplight function and follow proper self-test procedures per service manual.
Technical Notes:
C1129 DTC indicating a sensor fault does not always mean the sensor itself is bad. The issue may stem from the systems being monitored or even the sensor wiring. Proper diagnosis is essential.
C1129 Description
C1129 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for C1129 OBD-II Engine Trouble Code is: Fuel Rail/System Pressure — Too High.