B129D Lexus Lf Diagnostic Trouble Code

B129D Lexus Lf code definition:
B129D is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Lexus Lf.

B129D Lexus Lf is triggered when the bank 1 camshaft position sensor doesn't match the signal from the crankshaft position sensor. 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 B129D Lexus Lf diagnostic trouble code may include:

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

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)
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

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 :

Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. 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.

Process Tips

Diagnostic trouble code B129D Lexus Lf 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 B129D Lexus Lf.

Fortunately, B129D Lexus Lf is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.