DTC Advanced Diagnostics: P0134 (3.0L Engine)

DTC P0134: Rear Air/Fuel Ratio (A/F) Sensor (Bank 1, Sensor 1) Heater System Malfunction

General Description

Courtesy of HONDA, U.S.A., INC.

Courtesy of HONDA, U.S.A., INC.

The element impedance of the rear air/fuel ratio (A/F) sensor (bank 1, sensor 1) is monitored to determine whether the rear A/F sensor (bank 1, sensor 1) is active or not. The element temperature can be derived from the element impedance, and it is used for the malfunction detection. If the element temperature of the rear A/F sensor (bank 1, sensor 1) does not reach to a certain value after certain duration has passed since the heater is on, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Continuous
Sequence	None
Duration	10 seconds or more
DTC Type	Two drive cycles, MIL on

Enable Conditions

Condition	Minimum	Maximum
Elapsed time after the rear A/F sensor (bank 1, sensor 1) heater is on	30 seconds	-
Fuel feedback	Other than during fuel cut-off operation*

*: Continue for 10 seconds or more

Malfunction Threshold

The element temperature of the rear A/F sensor (bank 1, sensor 1) does not reach 1, 346 deg.F (730 deg.C) for at least 10 seconds even after 30 seconds has passed from the heater on.

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.

Rear A/F sensor (bank 1, sensor 1) failure

Confirmation Procedure

Operating Condition

Start the engine, and let it idle until the radiator fan comes on.

Diagnosis Details

Conditions for setting the DTC

When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC, the freeze data, and the on-board snapshot are stored.

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, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.