Engine Controls - Short Circuit O2 Sensor DTC's Stored

Short circuit faults concerning oxygen sensor stored in CDI control unit

Topic number LI49.20-P-053609

Version 1

Design group 49.20 Exhaust aftertreatment unit

Date 04-05-2012

Validity Model 164 with engine 642 and SA code U42 (BlueTEC (SCR) diesel exhaust treatment)

Reason for change

Complaint:
Engine diagnosis warning lamp CEL) lights up

The following faults may be stored in the CDI control unit:

Fault code 14E300

The output for the heater of oxygen sensor 1 (cylinder bank 1) has an electrical fault or an open circuit

Fault code 14E700

Oxygen sensor 1 (cylinder bank 1) has a short circuit to positive

Fault code 14E800

Oxygen sensor 1 (cylinder bank 1) has a short circuit to ground

Cause:
There may be transition resistances in the electrical lines or connectors between N319 (CDI control unit) and the component G312 (02 sensor upstream of catalytic converter).

Remedy:

1. Check connector between N3/9 (CDI control unit) and the component G3/2 (02 sensor upstream of catalytic converter) for correct connection / corrosion. Clean contacts and / or re-connect.

If there are connector issues, continue with step 2.

2. Process the test steps in Star Diagnosis for these fault codes. If a fault is found, follow the continuing diagnosis instructions.

If no faults are found, please submit the case to the DTS and clear the CEL.





Symptoms





Control Unit / Fault Code





Work Units