P0139

Tests 185 - 190:

Test 191:

SYMPTOM
P0139 - 1/2 O2 SENSOR SLOW RESPONSE

TEST NOTE
This symptom is diagnosed using the test P0133 - 1/1 O2 SENSOR SLOW RESPONSE.

WHEN MONITORED
Continuous for approximately the first 7 minutes operation. After warm-up, 20 - 60 mph, 1150 - 2500 rpm and 8.2 " - 15.7 " MAP

SET CONDITION
The oxygen sensor signal voltage is switching from below 0.35 volts to above 0.53 volts and back fewer times than required.

POSSIBLE CAUSES
- Exhaust leak
- O2S sensor ground circuit voltage drop
- O2S signal circuit voltage drop
- Wiring harness intermittent defect
- O2S defective