Check cable harness and connector between the exhaust gas aftertreatment control unit, E67, and the NOx sensor control unit, T131, and clean the connectors. Information about the electrical cables and pins on the control unit to which the component is connected is available in SDP3 under the tab Check for the relevant component, alternatively, Workshop manual section 03-35 Electronic control system, E67. If the fault is not rectified:Try connecting a different NOx sensor. The NOx sensor need only be connected electrically to verify that the fault is resolved.Remove the NOx sensor and inspect the damage to the cable harness between the NOx sensor control unit and the gauge. If damage is found on the cable harness rectify the cable routing so that the new NOx sensor is not damaged. Fit a new NOx sensor. To verify that the fault is rectified when renewing the NOx sensor:Switch off the power with the starter key, wait until button for the hazard warning signal extinguishes and then switch on the power again with the starter key. If the fault has been rectified, the fault code becomes inactive. Clear the fault code.

Diagnostic depth