Advanced Diagnostics
Advanced Diagnostics - DTC P219A: Air/Fuel Ratio Variation Of CylindersGeneral Description
The engine control module (ECM)/powertrain control module (PCM) measures the air/fuel ratio by the signal from the air/fuel ratio (A/F) sensor (sensor 1). If the air/fuel ratio varies between the cylinders, the signal of the A/F sensor (sensor 1) fluctuates while all cylinders complete the combustion procedure (two engine revolutions as one cycle). The ECM/PCM extracts the air/fuel ratio fluctuation of one cycle from the A/F sensor (sensor 1) signal, and integrates the extracted value at a specified duration. When the integrated value exceeds a specified value, the ECM/PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Enable Conditions
Malfunction Threshold
The integrated A/F sensor (sensor 1) output variation value is 30.446 or more in 6.9 seconds.
Confirmation Procedure
With the Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on.
2. Drive the vehicle at a steady speed between 55 - 75 mph (88 - 120 km/h) for at least 10 seconds.
3. Decelerate with the throttle valve fully closed.
4. Repeat driving pattern steps 2 through 3, four times.
5. Drive the vehicle in 4th gear at a steady engine speed 1,000 - 1,200 rpm.
6. Take 10 - 15 seconds to accelerate up to engine speed 3,000 rpm.
7. When the diagnosis does not finish, repeat driving pattern steps 5 through 6, four times.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the ECM/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 battery.