DTC Advanced Diagnostics: P101A
DTC P101A:Variable Valve Timing Control (VTC) B Advance Malfunction

General Description

The variable valve timing control (VTC) system controls the phase of the intake camshaft and exhaust camshaft. It uses oil pressure to operate the VTC actuator B so the valve timing is optimized depending on driving conditions. The powertrain control module (PCM) monitors the phase control command value and the actual phase value of exhaust camshaft using the camshaft position (CMP) sensor B. When an over-retarded camshaft phase angle, which the over-retarded angle is predetermined value greater than the commanded values, continues to exist while the VTC is either active or inactive or a retarded phase angle of the exhaust camshaft is greater than the predetermined value while the VTC is inactive, a malfunction is detected and a DTC is stored.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
4.1 seconds or more
DTC Type
One drive cycle, MIL on

Enable Conditions
Condition
Minimum
Maximum
Elapsed time after starting (or stalled) the engine
0.5 second
–
Other
In the case the engine was stalled, the exhaust camshaft angle must be 10 ° or more for at least 2 seconds after restarting the engine

Malfunction Threshold
Either one of the condition is met for at least 4.1 seconds:
The controlling value of a retarded exhaust camshaft phase angle is 48.8 ° greater than the commanded value while the VTC is either active or inactive.
The controlling value of a retarded exhaust camshaft phase angle is 20.0 ° greater than the commanded value which is 0 ° while the VTC is inactive.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
VTC actuator B abnormal retarded phase angle
VTC oil control solenoid valve B stuck

Confirmation Procedure
Operating Condition
Start the engine, and let it idle.

With the HDS
None.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.