Chrysler PT Cruiser 2001 Service Manual Supplement page 2555

P0172-1/1 FUEL SYSTEM RICH —
TEST
13 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
14 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 15
→ Repair the high resistance on the O2 Sensor Signal circuit.
No
15 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 ground circuit at the O2 Sensor harness connector
and ground.
Start the engine.
Allow the engine to idle.
Is the voltage below 0.10 volt?
Yes → Go To 16
→ Repair the high resistance on the O2 Sensor ground circuit.
No
16 Replace the O2 Sensor in accordance with the Service Information.
Attempt to operate the vehicle within the Freeze Frame parameter that where noted.
It may be necessary to operate the vehicle for more than 2 drive cycles.
NOTE: Monitor the O2 Sensor voltage ensure good O2 voltage activity.
Does the DTC reset?
Yes → Replace and program the Powertrain Control Module in accor-
→ Test Complete.
No
Continued
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
DRIVEABILITY - GAS
95
APPLICABILITY
All
All
All
All