Electrical Testing - Introduction Land Rover Freelander L314

General

The following guidelines are intended to ensure the safety of the operator whist preventing damage to the electrical and electronic components fitted to the vehicle. Where necessary, specific precautions are detailed in the relevant sections of this document, reference of which should be made prior to commencing repair operations.

Equipment - Prior to commencing any test procedure on the vehicle, ensure that the relevant test equipment is working correctly and any harness or connections are in good condition. This particularly applies to mains lead or connections.

Polarity - Never reverse connect the vehicle battery and always observe correct polarity when connecting test equipment.

High Voltage Circuits - Whenever disconnecting live ht circuits, always use insulated pliers and never allow the open end of the ht lead to come into contact with other components, particularly ECU's. Since high voltage spikes can occur on the terminals of the coil while the engine is running, exercise caution when measuring the voltage at these points.

Connectors and Harnesses - The engine compartment of a vehicle is a particularly hostile environment for electrical components and connectors. Always ensure these items are dry and oil free before disconnecting and connecting test equipment. Never force connectors apart either by using tools or by pulling on the wiring harness. Always ensure locking tabs are disengaged before removal and note orientation to enable correct reconnection. Ensure that any protective covers and substances are replaced if disturbed.

Before removing a faulty component, refer to the Workshop Manual for removal procedures.

Ensure the ignition switch is turned to the 'OFF' position, the battery is disconnected and any disconnected harnesses are supported to avoid any undue strain at the terminals. When replacing the component keep oily hands away from electrical connection areas and push connectors home until any locking tabs fully engage.

Two Land Rover harness repair kits are available. Range Rover (LM) harness repairs can be carried out using repair kit LRT-86-010. Range Rover (LP), Discovery Series II, and Freelander (01MY onwards) are covered by Harness Repair Kit LRT-86-010/1.

The Harness Repair Kits contain the following components to enable the technician to carry out 'Right First Time' repairs

1. z Crimping pliers.
2. z Wire cutter/stripping tool.
3. z Heat shrink tubing.
4. z Wire color identification rings.
5. z Splice connectors.
6. z Pre-terminated leads (connector pins with 90 mm wire 'pig tails').
7. z Connector housings.
8. z Connector pin extractor tools.

Note. Replacement connector housings and pre-terminated leads can be ordered from: SPX UK Ltd, Genoa House, Everdon Park, Daventry, Northants, NN11 5YJ. Tel: +44 (0)1327 303400.

In order to carry out a repair, a suitable hot air gun and heat resistant blanket will also be required. These can be sourced locally.

The kits can be used to make repairs to all except the following

1. z Any Media Orientated System Transport (MOST) network harnesses.
2. z Supplementary Restraint System (SRS) firing circuits.
3. z ABS wheel speed sensors with molded connectors (Defender, Discovery Series II, and pre-02MY Freelanders only).
4. z Any wires with a Cross Sectional Area (CSA) of greater than 4.0 mm.

If damage occurs in any of these areas, an overlay harness must be used.

GENERAL ANTI-LOCK BRAKING SYSTEM

When diagnosing an electrical fault, follow the steps below

1. Read the circuit description appropriate to the reported fault to ensure a good understanding of circuit operation.
2. Study the power distribution, fuse details and earth distribution diagrams and identify other circuits which share fuses and/or earth points. Check whether these circuits operate correctly.
3. Using the photographs contained in the Connector section, locate a point on the circuit (approximately half way between supply and earth) which is easily accessible.
4. Check that the pin-out details of the connector are correct and that the correct signals exist at the correct terminals.
5. Using the marker pen supplied (or other suitable non-permanent marker pen), mark the parts of the circuit you have verified.
6. Continue to the next point on the circuit which is easiest to access and repeat the above.
7. Continue with this approach until a fault is found, rectify the fault and then verify that the circuit operates correctly.

The following list contains wire color codes used on the vehicle harness's.

COLOR CODE CHART