C1129 Alldays 30 Diagnostic Trouble Code

C1129 Alldays 30 code definition:
C1129 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Alldays 30.

C1129 Alldays 30 is described as Fuel Rail Pressure Sensor Circuit Malfunction. This code is strictly about the incoming signal from the FRP (fuel rail pressure) sensor falling below the calibrated limit for a certain period of time. Any code that causes the vehicle's engine to die while running should be fixed as soon as possible, as it can be dangerous for both the vehicle and the passengers of the vehicle.

Symptoms

Symptoms of a C1129 Alldays 30 diagnostic trouble code may include:

Corroded or damaged connector
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Lack of power
Diminished fuel efficiency

Possible Causes :

Faulty IMRC actuator/sensor
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

Common Misdiagnoses

Exhaust Gas Recirculation System Valve 1 Problem
BBV Sensor Circuit Low Voltage Problem
Transmission Engaged At High Throttle Angle Problem
Cruise Inhibit Control Circuit Problem
TFP Valve Position Switch-Drive Without Drive Ratio Problem

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. Look at the plug wires to make sure they are not burnt or laying on the exhaust. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C1129 Alldays 30 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C1129 Alldays 30.

Fortunately, C1129 Alldays 30 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.