P0139

Test 1 - 3:

Test 4 - 5:

SYMPTOM
P0139-O2 SENSOR 1/2 SLOW RESPONSE

TEST NOTE
This symptom is diagnosed using the test P0133-O2 SENSOR 1/1 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. amb/batt temp >44 °F, Baro >22.13 inches H2O, battery >10.5 volts, MAP >11.79 & <18.15 inches H2O, RPM >1350 & <2200 and VSS >50 and <65.

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

POSSIBLE CAUSES
- Good trip equal to zero
- Exhaust leak
- Resistance in the O2 sensor signal circuit
- Resistance in the (K4) sensor ground circuit
- O2 sensor