C0946 Vaz 2120 Diagnostic Trouble Code

C0946 Vaz 2120 code definition:
C0946 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Vaz 2120.

C0946 Vaz 2120 is described as Oxygen Sensor Circuit No Activity Detected Bank 2 Sensor 1. This code appears when the PCM (powertrain control module, also known as ECM or engine control module in other brands) remains at or close the 0.450 set voltage point. So if the problem persists despite of your diagnosis, then you should never hesitate to take your vehicle to your dealer or to a qualified mechanic.

Symptoms

Symptoms of a C0946 Vaz 2120 diagnostic trouble code may include:

Faulty O2 Sensor
Lack of power
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Diminished fuel efficiency

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)
Fuel with a large percentage of sulfur will clog the DPF quickly

Common Misdiagnoses

Crankshaft Position Sensor Circuit Performance Problem
TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
Kick-Down Switch Failed Short Problem

Repair Processes :

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. 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. 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 C0946 Vaz 2120 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 C0946 Vaz 2120.

Fortunately, C0946 Vaz 2120 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.