U1177 Diagnostic Trouble Code

U1177 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a U1177 diagnostic trouble code may include:

Possible spark knock (detonation / pre-ignition)
Poor fuel economy
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code U1177 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 U1177.

Fortunately, U1177 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U1177 Trouble Code For Specific Cars

U1177 Toyopet Pt Multi-faults - Bank 1 - With Low Side Shorts
U1177 Hupmobile 618 Rotor Calibration Fault
U1177 Mercedes S 63 Air Bag Crash Sensor #1 Feed/Return Circuit Open
U1177 Hafei New Quing Passenger Side Crash Sensor Communication Fault (Non SCP)
U1177 Holden Vp Pressure Control Solenoid "A" Short Circuit
U1177 Bizzarrini Bz-2001 Brake Switch Circuit Failure
U1177 Lagonda 2-litre Shift Solenoid D Electrical