B1122 Db Coach Diagnostic Trouble Code

B1122 Db Coach code definition:
B1122 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Db Coach.

B1122 Db Coach 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. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

Symptoms

Symptoms of a B1122 Db Coach diagnostic trouble code may include:

Hesitation upon acceleration
Excessive exhaust leak
Rich or lean exhaust
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
Some aftermarket accessories and performance modifications

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 :

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 all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve.

Process Tips

Diagnostic trouble code B1122 Db Coach 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 B1122 Db Coach.

Fortunately, B1122 Db Coach is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.