P0171

ADAPTATION FAULTY





Symptom Of Fault.
The CHECK ENGINE lamp (MIL) is on.
Impaired driveability, hunting idle
Any other diagnostic trouble codes (such as low fuel, pressure sensor, closed loop, misfiring).

Conditions.
Ignition switch in ON position.
P0170: All-embracing DTC.
P0171: Adaptation > 100%
P0172: Adaptation < -100%

Diagnostic Help.
If the adaptation fault occurred on account of low fuel level, this is indicated by DTC P1416 also being generated.

Adaptation can be ascertained using an ISAT scan tool.

- Select "READ FUNCTIONS".
- Select "GLOBAL ADAPTATION".

Current adaptation ±100% will be shown.

Checking The Wiring
Intermittent faults may occur as a result of occasional short circuits and breaks in the wiring. Jiggle the leads and in-line connectors at several places and in different directions to reveal faults in the wiring harness. Observe the multimeter, ISAT scan tool or test lamp while carrying out this check.





Diagnostic Procedure.
1. Check additional diagnostic trouble codes in the Trionic system

^ Read out all the diagnostic trouble codes with the ISAT scan tool.
^ P1416
^ P0105-P0135
^ P0441-P0445
^ P1170-P1172

Are any of the above diagnostic trouble codes present?
YES: Continue fault diagnosis for the relevant diagnostic trouble code.
NO: Continue with point 2.

2. Check for air leakage
Check that no air leakage occurs at the following points:

^ the hose between the pressure sensor and intake manifold
^ the hose between the fuel pressure regulator and intake manifold





3. Check pressure sensor operation

- Turn the ignition switch to the ON position and then back to the OFF position.
- Connect an ISAT scan tool.
- Select ':READ FUNCTIONS".
- Select "INTAKE PRESSURE".

The ISAT scan tool should show a reading of about 102 kPa (NOTE: the reading is dependent on air pressure).

- First build up a pressure of 0.6 bar and then create a vacuum of -0.6 bar. Use a pressure gauge and a pressure/vacuum pump.

The ISAT scan tool should show readings of 160 ± 5 kPa and 40 ±5 kPa respectively (the ISAT scan tool readings may be somewhat lower at high altitudes). The measurement is intended to detect any shift in the operating range of the pressure sensor.

Are the readings OK?
YES: Continue with point 4.
NO: Change the pressure sensor and continue with point 5.

4. Other checks

Check:

^ that the EVAP canister purge valve is closed in the zero-voltage state
^ fuel pressure and flow
^ that no air leakage occurs in the exhaust system ahead of the front heated oxygen sensor or at its mounting.

Checks OK?
YES: Continue with point 5.
NO: Rectify the fault and proceed to point 5.





5. Final check:

- Clear the diagnostic trouble code.
- Implementation of driving cycle:

^ Start the engine and run it at idling speed until the temperature of the coolant reaches 60°C (140°F.
^ Drive the car at 2,000-3,000 rpm and a load of 60-120kPa for about 1 minute.
^ Since throttle position changes should be avoided, as level a road as possible should be chosen.

- Evaluation of the driving cycle:
- Connect an ISAT scan tool.
- Select "READ FUNCTIONS".
- Select "GLOBAL ADAPTATION".

Is the ISAT scan tool reading "0%"?
YES: Repeat the driving cycle.
NO: The ISAT scan tool reading is > 50% or < -50%.
Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The ISAT scan tool reading is < 50% or > -50%.
The remedial measure taken was correct.