VSS - DTC P0500 Set, Engine Misfire: Overview

06/27/97

19/03/97/NAS

SUBJECT
PRIDE - Road Speed Transducer Fault Diagnosis

MODEL
Discovery

AFFECTED VEHICLES
LP
LH
LJ 1996-1997 MY
LD

DETAIL

The roadspeed transducer, Vehicle Speed Sensor, (VSS) is a reed type switch that is opened and closed by a rotating magnet driven by the transfer box Output shaft. The signal from the VSS switches from battery voltage to 0 volts each time it opens and closes. This happens 8000 times per mile or approximately every inches of vehicle movement. The signal, viewed on an oscilloscope, is a simple square wave pattern. This TIB discusses two problems related to VSS fault:

^ P-code P0500 VSS Fault
^ Misfire caused by intermittent VSS

The diagnostic steps and repair procedures detailed on the following pages were developed as an element of the Land Rover Way OPERATION PRIDE, This TIB provides a library location for PRIDE information within the Land Rover North America technical literature system.

ACTION REQUIRED

Upon customer complaint for the symptoms outlined, perform the specified repairs.

PARTS INFORMATION





Required Parts:
AMR1253 - Roadspeed Transducer (VSS)

Required Tools:
Snap-on(R) P.A.C.

PROCEDURE

TestBook

1. Hook up TestBook and follow directions to retrieve fault codes.

2. Complete a DTCR along with freeze frame data and FAX to LRNA.

3. Follow diagnostic directions from TestBook in order to locate problem.

4. If TestBook tests do not resolve the problem some basic diagnostics should be followed.

P0500 Fault

This VSS signal is used for four functions:

1. Speedometer,
2. Cruise control,
3. Input into GEMS, and
4. Service reminder light

Failure of GEMS to receive a signal from the VSS will cause a P0500 fault to be flagged.

WARRANTY

Normal warranty procedures and policies apply.

COMP. CODE

SRO

19.22.97 - Time 1.00 hr.
DTCR and Drive Cycle "B" Per Bulletin W96-007

88.30.14 - Time 0.4 hr.
VSS Replacement

88.30.89.22 - Time 0.15 hr.
VSS Test