Upshift Lamp System Check (Manual Transmission Only) - Isuzu 1999 RODEO Workshop Manual

Upshift Lamp System Check (Manual Transmission Only)

Circuit Description
The shift lamp indicates the best transmission shift point
for maximum fuel economy.
The lamp is controlled by the Power Train Control Module
(PCM) and is turned "ON" by grounding the YEL/GRN
wire.
The PCM is used information from the following inputs to
control the upshift lamp.
f Engine Coolant temperature (ECT) Sensor
f Throttle Position Sensor
f Vehicle Speed Sensor
f Engine Speed
The PCM uses the measured RPM and the vehicle speed
to calculate what gear the vehicle is in.
It's this calculation that determines when the upshift lamp
should be turned "ON".
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation.
connections or a damaged harness.
Inspect the PCM harness and connector for proper
mating, broken locks, improperly formed or damaged
terminals, poor terminal-to-wire
damaged harness.
Test Description
1. This should not turn "ON" the up-shift lamp. If the
lamp is "ON", there is a short to ground in YEL/GRN or
a fault PCM.
2. This checks the upshift lamp circuit up to the PCM
connector.
If the up-shift lamp illuminates, then the PCM
connector is faulty or PCM does not have the ability
to ground the circuit.
6E1–105
D06RX063
Check for poor
connection and