DTC P1172
DTC P1172: Air/Fuel Ratio (A/F) Sensor (Sensor 1) Circuit Out of Range High
General Description
If a malfunction causes the air/fuel ratio (A/F) sensor (sensor 1) signal to the powertrain control module (PCM) to deviate from the normal control area, the A/F sensor (sensor 1) may still become active after the engine starts, but the air/fuel feedback does not start normally and the emissions deteriorate. When the A/F sensor (sensor 1) output is out of the normal area, and this condition continues after the A/F sensor (sensor 1) is active, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 7.0 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Malfunction Threshold
A malfunction is detected when the A/F sensor (sensor 1) output voltage is 4.9 V or more.
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.
- A/F sensor (sensor 1) 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, then let it idle.
- Air/fuel ratio feedback is started while idling, hold for at least 7 seconds.
[ ]: HDS Parameter
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.