B3691 Diagnostic Trouble Code

B3691 is a kind of OBD-II Diagnostic B-Body 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 B3691 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 :

Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors.

Process Tips

Diagnostic trouble code B3691 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 B3691.

Fortunately, B3691 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B3691 Trouble Code For Specific Cars

B3691 Italdesign Legram SCP (J1850) Lack of Acknowledgment for Audible Warnings
B3691 Standard Vanguard Lamp Keypad Output Short Circuit To Battery
B3691 Mazda 818 Transmission Transfer Case Contact Plate Ground Return Open Circuit
B3691 Peugeot 305 EGI Temperature Sensor Failure
B3691 Nissan Almera Tino Climate Control A/C Pressure Switch Circuit Open
B3691 Lmx Sirex through P0580 Reserved for Cruise Codes
B3691 Imperial Custom