DTC Advanced Diagnostics: P2A01
DTC P2A01:Secondary Heated Oxygen Sensor (Secondary HO2S) (Sensor 2) Circuit Range/Performance Problem

General Description

The secondary heated oxygen sensor (secondary HO2S (sensor 2)) detects the oxygen density in the exhaust gas and converts it into electrical signals. If the secondary HO2S (sensor 2) output voltage is a set value for a specified time, the powertrain control module (PCM) detects a malfunction and stores a DTC.

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

Enable Conditions
Condition
Minimum
Maximum
Secondary HO2S (sensor 2) output voltage [HO2S S2]
–
1.0 V
State of the engine
Running
[ ]: HDS Parameter

Malfunction Threshold
The secondary HO2S (sensor 2) output voltage [HO2S S2] is 1.54 V or less for at least 6 seconds after the secondary HO2S (sensor 2) is judged that it is normally activated (1.0 V or less as a value).

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.
Secondary HO2S (sensor 2) failure
PCM internal circuit failure

Confirmation Procedure
Operating Condition
Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on.

With the HDS
None.

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 and the freeze data 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, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.