U0122 Railton 20 shows up when there's an electrical problem that causes the fuel volume regulator to malfunction and open. It's quite an unusual problem and likely intermittent. Other symptoms that may indicate this problem are when the Check Engine Light illuminates and when there is a visible lack of engine power.
SymptomsSymptoms of a U0122 Railton 20 diagnostic trouble code may include:
Possible Causes :
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. 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.
Diagnostic trouble code U0122 Railton 20 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 U0122 Railton 20.
Fortunately, U0122 Railton 20 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.