Specifications

TEST ACTION APPLICABILITY
1 NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Test drive the vehicle.
Monitor the DRB for ECM DTCs.
Did this DTC set again?
All
Yes → Go To 2
No → Go To 9
2 Turn the ignition off.
Using the Service Information wiring diagrams, inspect the wiring and connectors
between the ECM and the O2 sensor for damage, corrosion, poor terminal contact or
other problems.
Were any problems found?
All
Yes → Clean, repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No → Go To 3
3 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Power Supply circuit at the
O2 harness connector cavity 4.
Does the test light illuminate brightly?
All
Yes → Go To 4
No → Repair the Power Supply circuit for an open or short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the O2 Sensor harness connector.
Disconnect the ECM harness connectors.
Perform the following resistance measurementsfrom theO2 harness connector to the
ECM harness connector.
O2 Sensor Cavity 1 to ECM Cavity C1-15.
O2 Sensor Cavity 2 to ECM Cavity C1-40.
O2 Sensor Cavity 3 to ECM Cavity C1-72.
O2 Sensor Cavity 5 to ECM Cavity C1-62.
O2 Sensor Cavity 6 to ECM Cavity C1-39.
Is the resistance below 10.0 ohms for each measurement?
All
Yes → Go To 5
No → Repair the circuit(s) that measured above 10.0 ohms for an open.
Perform ROAD TEST VERIFICATION - VER-2.
135
DRIVEABILITY - DIESEL
P2026-O2 SENSOR CIRCUIT FAULT — Continued