B268B Nissan 260 Diagnostic Trouble Code

B268B Nissan 260 code definition:
B268B is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Nissan 260.

B268B Nissan 260 is defined as Knock Sensor Circuit Range Performance (Bank 1 or Single Sensor). This refers to camshaft timing, which in this case is over-retarded. There are two wires dedicated for each coil; one is battery feed which usually comes from the distribution center, and the other one for the coil driver circuit from the PCM. The PCM grounds or ungrounds the circuit to activate or deactivate the coil.

Symptoms

Symptoms of a B268B Nissan 260 diagnostic trouble code may include:

Blown fuse (if applicable)
Engine surge
Reduction in engine performance, especially at low RPM levels
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
Kick-Down Switch Failed Short Problem
Park/Neutral Postion (PNP) Switch Circuit Engine Torque Signal Circuit Problem

Repair Processes :

Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. 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 engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition.

Process Tips

Diagnostic trouble code B268B Nissan 260 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 B268B Nissan 260.

Fortunately, B268B Nissan 260 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.