P308B Volvo 122 Diagnostic Trouble Code

P308B Volvo 122 code definition:
P308B is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Volvo 122.

P308B Volvo 122 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. Other symptoms that may indicate this problem are when the Check Engine Light illuminates and when there is a visible lack of engine power.

Symptoms

Symptoms of a P308B Volvo 122 diagnostic trouble code may include:

Engine surge
Blown fuse (if applicable)
Lack of power
Rich or lean exhaust

Possible Causes :

Faulty IMRC actuator relay (if equipped)
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory Problem

Repair Processes :

Now, clear the codes and test-drive the vehicle to see if the code is reset. 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. Look at the plug wires to make sure they are not burnt or laying on the exhaust.

Process Tips

Diagnostic trouble code P308B Volvo 122 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 P308B Volvo 122.

Fortunately, P308B Volvo 122 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.