B3949 Code:

OBD-II Diagnostic Body (B) Trouble Code

Possible Cause

The reason for B3949 the speedometer may fluctuate wildly or fail to operate, the engine may stall when coming to a stop, engine misfire, sag, stall, or hesitation, a stored code, and possibly an illuminated service engine soon lamp.

Common Symptoms

  1. Corroded connectors, at or near the fuel shutoff valve, frequently test appropriately until the circuit is loaded, at which time the circuit is compromised due to excessive resistance
  2. Should all system circuitry and sensors check out and the transmission is in good working order, suspect a faulty PCM but keep in mind that PCM failure is rare and PCM replacement will require reprogramming.
  3. An output speed sensor is used to provide the PCM with a transmission output speed signal
  4. Individual control module failure is rare but possible

Similar Problems

IC Module 4X Ref Circuit Intermittent, No Pulses
IC Circuit High Voltage
TFP Valve Position Switch-Drive Without Drive Ratio

B3949 Troubleshooting

When you put your foot down on the brakes you expect your car to quietly slow down and come to a stop. The power your foot applies on the brake pedal is assisted by hydraulic pressure. Your foot's force engages a piston and caliper with brake pads attached (bonded abrasive and heat resistance metal or ceramic) to put pressure on the rotor. B3949 OBD2 specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.

How to turn off B3949 check engine light ?

There are two ways to turn off the check engine light:

A repair technician can do so once repairs have been made.
The OBD II can automatically turn it off when it fails to detect the problem after several diagnostic cycles.

EngineTroubles.com Logo

Copyright © 2017 | https://www.enginetroubles.com | All Rights Reserved.