Chrysler PT Cruiser 2001 Service Manual Supplement page 2549

P0171-1/1 FUEL SYSTEM LEAN —
TEST
10 Turn the ignition off.
NOTE: Visually inspect the related wiring harness. Look for any chafed,
pierced, pinched, or partially broken wires.
Note: Visually inspect the related wiring harness connectors. Look for
broken, bent, pushed out, or corroded terminals.
Note: Refer to any Technical Service Bulletins (TSB) that may apply.
Perform a wiggle test on the related wiring harnesses with the engine running.
Watch for the Good Trip Counter to change to 0.
Were any problems found?
Yes → Repair wiring harness/connectors as necessary.
→ Go To 11
No
11 Turn the ignition off.
Connect a Vacuum Gauge to a Manifold Vacuum source.
Start the engine.
Allow the engine to idle.
Note: If engine will not idle, maintain a constant RPM above idle.
Using the DRB, monitor the MAP Sensor vacuum value.
Is the DRB reading within 1 of the Vacuum Gauge reading?
Yes → Go To 12
→ Replace the MAP Sensor.
No
12 Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?
Yes → Repair as necessary.
→ Test Complete.
No
13 NOTE: Ensure the voltmeter leads meet the terminals in the connector and
that there is good terminal to wire connection.
NOTE: Ensure the voltmeter leads are connected for positive polarity
Backprobe between the O2 Sensor Signal circuit at the O2 Sensor harness connector
and PCM harness connector.
Start the engine.
Allow the engine to idle.
Is the voltage below 0.10 volt?
Yes → Go To 14
→ Repair the high resistance on the O2 Sensor Signal circuit.
No
Continued
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
DRIVEABILITY - GAS
89
APPLICABILITY
All
All
All
All