U0687 Diagnostic Trouble Code

U0687 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 U0687 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Hesitation upon acceleration

Possible Causes :

Some aftermarket accessories and performance modifications
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code U0687 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 U0687.

Fortunately, U0687 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0687 Trouble Code For Specific Cars

U0687 Smart Coupe Lamp ABS Warning Output Circuit Short To Ground
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U0687 Du Pont Touring Illuminated Entry Input Open Circuit
U0687 Chevrolet Sail EIC Switch-2 Assembly Circuit Short To Battery
U0687 Amc Matador Air Suspension Gate Solenoid Output Circuit Failure
U0687 Mazda Clef Transmission Transfer Case Differential Lock-Up Solenoid Short Circuit To Ground
U0687 Humber Imperial Right Rear Sensor Circuit Failure