P0139

Test 1:

Tests 2 - 6:

Tests 7 - 12:

Test 12:

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
Start engine. Allow engine to idle. For 1st part of test, if limits are exceeded, test passes. If not, 2nd part of test runs. Ambient/Battery temperature > 44 °F, Baro > 22.13 "H20, Battery > 10.5 volts, MAP > 11.79 & < 18.15 "H20, RPM > 1350 & < 2200 and VSS > 50 mph & < 65 mph.

SET CONDITION
The oxygen sensor signal voltage is switching from below 0.39 volts to above 0.58 volts and back fewer times than required.

POSSIBLE CAUSES
- Exhaust leak
- O2 sensor heater feed circuit open
- O2 sensor heater ground circuit open
- O2 sensor sensor ground circuit voltage drop
- O2 sensor signal circuit voltage drop
- O2 sensor
- Wiring harness intermittent problem