Mazda MX-6 1998, Руководство по ремонту, Страница: 239 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
DTC P0142
P1143
P1144
Heated oxygen sensor (Rear) (H 02S 13) circuit malfunction
Lack of heated oxygen sensor (Rear) (H 02S 13) switch sensor indicates lean
Lack of heated oxygen sensor (Rear) (H 02S 13) switch sensor indicates rich
DESCRIPTION
• DTC P0142 indicate the output voltage of the downstream heated oxygen sensor is less
than some calibratable functional window.
• DTC P1143 and P1144 can only retrieved during key on engine running (KOER) Self-Test
when the fuel control Is ramped rich and lean and monitored for a voltage change on the
rear heated oxygen sensor.
[Possible Cause]
• Wiring Concerns • Other Concerns
• Pinched, shorted, and corroded wiring and pins • Exhaust leaks
• Crossed sensor wires • Contaminated or damaged sensor
STEP
INSPECTION ACTION
1
DTCS P0142 MONITOR DOWNSTREAM
HEATED OXYGEN SENSOR OUTPUT
VOLTAGE FOR ACTIVITY.
• Are any of the above concerns present?
Yes SERVICE as necessary.
RESET PCM to completely clear the DTCs.
tr
After Repair Procedure
COMPLETE a OBD II Drive Mode.
RERUN OBD Test.
No
Continuous Memory DTCs P0156:
Go to next step.
All others:
Go to step 3.
2
CHECK FOR KOER DTCS P1143 AND
P1144
• Key off.
• NGS tester connected.
• Key on.
• Engine at 2,000 rpm for 3 minutes.
• Activate KOER Self-Test.
• Check for DTCs.
• Are DTCs P1143 or P1144 present?
Yes Go to nest step.
No Fault may be intermittent.
Intermittent poor connection or component malfunction
(SERVICE or REPLACE as necessary).
Go to ENGINE SYMPTOM TROUBLESHOOTING No.27.
3 CHECK EXHAUST SYSTEM FOR LEAKS
Note
• Any exhaust leaks between the engine and
the end of three way catalytic converter
may cause DTCs P0142.
• Key off.
• Raise vehicle.
• Inspect the following:
• Exhaust flanges for leaks
• Heated oxygen sensor tightening torque
• Check for punctures and cracks in
catalyst and pipes leading to them.
• Are there any exhaust leaks?
Yes REPLACE or SERVICE as required.
RESET PCM to completely clear the DTCs.
c r After Repair Procedure
COMPLETE a OBD II Drive Mode.
RERUN OBD Test.
No Go to next step.
01-01B-33