TEST
ACTION
APPLICABILITY
5
Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and O2 Sensor harness connector cavities 1,
2, 3, 5, and 6.
Is the resistance above 1000 ohms for each measurement?
All
Yes
→ Go To 6
No
→ Repair the circuit(s) that measured below 1000 ohms for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
6
Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the ECM harness connectors.
NOTE: The circuits connecting the O2 Sensor and the ECM are single
circuits and do not contain any splices. There should be NO continuity from
one circuit to the other.
Using an ohmmeter, check the O2 Sensor circuits for shorts together (resistance
below 1000 ohms)..
Is the resistance from any O2 Sensor circuit to another below 1000 ohms?
All
Yes
→ Repair the circuits that measured below 1000 ohms for a short
together.
Perform ROAD TEST VERIFICATION - VER-2.
No
→ Go To 7
7
Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the Engine Control Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the Engine Control Relay
connector.
Turn the ignition on.
Measure the voltage of O2 Sensor harness connector cavities 1, 2, 3, 5, and 6.
Is the voltage below 1.0 volts for each measurement?
All
Yes
→ Go To 8
No
→ Repair the circuit(s) that measured below 1000 ohms for a short to
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
8
Turn the ignition off.
Replace the O2 Sensor in accordance with the Service Information.
Turn the ignition on.
With the DRBIII
t, erase the ECM DTCs.
Test drive the vehicle.
With the DRBIII
t, read the ECM DTCs.
Did this DTC set again?
All
Yes
→ Replace the ECM in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No
→ Test Complete.
136
DRIVEABILITY - DIESEL
P2026-O2 SENSOR CIRCUIT FAULT —
Continued