Checking Leads And Connectors

CHECKING LEADS AND CONNECTORS

Many faults in the electrical system may stem from poor wiring and terminals. These faults can be caused by interference from other electrical systems and mechanical or chemical damage.





Check Connections Visually
^ Whenever a connector is disconnected for measurement or inspection, the terminals should be checked visually.

Checks:
- Look for oxidation which may cause poor contact.
- Check that the tabs and sockets are undamaged, that they are properly inserted into the connector and that the conductor is properly connected to the tab/socket. Check in particular the tabs and sockets for the relevant DTC.
- Test with a separate male tab to see if the female tab provides adequate contact; check also that it is properly attached by pulling lightly on the male tab.





Circuit Breaks
^ Breaks in leads are indicated by the loss of a function. Chafed or worn leads which have come loose are common causes of faults.

Checks:
- Disconnect the connectors at both ends of the lead.
- Check the connectors visually. Measure resistance by connecting an ohmmeter to each end.

The ohmmeter should show approx. 0 Ohms if the lead is intact.

Checking Intermittent Breaks:
- Check the lead visually.
- Shake the lead and pull the connections gently during measurement to locate fault.





Short Circuiting to Ground
^ Short circuiting between a live lead and ground usually causes the fuse to blow or a loss of function when the lead goes live.

Checks:
- Activate all the switches and sensors in the circuit and check if the fuse has blown.
- Disconnect the connectors for the components in the circuit so that they do not affect the measurements.
- Use an ohmmeter to measure resistance between lead and ground

The ohmmeter should show infinite resistance if no components are connected.





Checking Intermittent Short Circuiting to Ground:
- Check the lead visually.
- Shake lead and pull connections gently during measurement to locate fault.





Short Circuiting to Voltage Supply
^ Short circuiting between a lead and voltage supply usually causes the fuse to fail when the lead becomes live or may case the loss of a function or functions.

Checks:
- Use a voltmeter to check at various points along the circuit while operating the switches and sensors.
- The voltage indicated by the voltmeter depends on the particular circuit and the status of switches and sensors. Use the wiring diagram to determine the correct value.
- Use an ohmmeter to measure between the suspected leads to locate the short circuits between them.

The ohmmeter should show infinite resistance when measuring between leads which are not connected to each other in the circuit.





Checking Intermittent Short Circuiting to Voltage Supply:
- Check the lead visually.
- Shake lead and pull connections gently during measurement to locate the fault.





Loose Connection (Connectors)
^ Loose connections in the connectors are caused by oxidation of the pins and sockets or by poor connection of the leads.
^ Loose connections cause the same faults as intermittent breaks in the lead.

Checks:
- Check the connections visually.
- Shake lead and pull connections gently during measurement to locate the fault.
- Check in particular the tabs and sockets for the relevant DTC.





- Always check the control module and control module box connectors to ensure that their pins and sockets are not bent or damaged, this may cause a fault.
- Check in particular the tabs and sockets for the relevant DTC.

NOTE: When checking the control module, do not remove it from the car until the main relay has cut the voltage supply, which may take up to 150 seconds after the ignition has been switched off.





Contact Resistance and Oxidation
^ Resistance in contacts, leads and connectors should be 0 Ohms. However, a certain degree of resistance is present owing to oxidation of the connections.
^ If this resistance is too great, it gives rise to functional interference. Just how much resistance is permissible without giving rise to functional interference varies with the load on the circuit. A general guide is a few ohm.

Checks:
- Check the connections visually.

NOTE: When checking the control module, do not remove it from the car until the main relay has cut the voltage supply, which may take up to 150 seconds after the ignition has been switched off.





Cleaning of Female Contacts and Male Pins

NOTE: Do not use rust removal spray or grease on the HO2S connectors.

- Ignition OFF.
- Disconnect the battery's minus cable.
- Use compressed air to clean the detached connector.
- Spray the connector halves with rust removal spray P/N 1161422 (P/N 1161435 USA/CDN).
- Blow clean with compressed air.





Greasing Female Contacts

NOTE: Do not put grease inside the casing.

- Pack connector halves with grease, P/N 1161417, directly from the tube.
- Check that all terminal socket cavities are filled.





- Use a loose male pin to ensure that contact in sockets is good. The pin should remain in position when pulled gently.