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Low Engine Coolant Indicator Always On Opel GT II

Engine Cooling ~384 words

Low Engine Coolant Indicator Always On

Diagnostic Instructions

•Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
•Review Strategy Based Diagnosis for an overview of the diagnostic approach.
•Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Coolant Level Switch SignalLamp OFFLamp ONLamp OFF--
Low Reference--Lamp ON----

Circuit/system Description

The low engine coolant level indicator lamp on the instrument panel cluster (IPC) is controlled by the body control module (BCM) through the low speed GM LAN Serial Data line to the engine control module (ECM). When the engine coolant level switch is open for 30 seconds or longer indicating low coolant, the BCM will signal the ECM to turn ON the Coolant level lamp. The lamp will also illuminate for approximately 3 seconds during the display test at the start of each ignition cycle.

Reference Information

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference (Except Opel Gt)

•Circuit Testing
•Connector Repairs
•Testing for Intermittent Conditions and Poor Connections
•Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/system Verification

  1. Ignition ON, observe the scan tool coolant level switch. The reading should be OK with the coolant at the proper level.
  2. Turn ON the ignition with the engine OFF.
  3. Command the instrument cluster indicators ON and OFF with a scan tool.
  4. The low coolant indicator lamp should turn ON and OFF on command.
  5. The low coolant indicator should be OFF with the engine coolant at the proper level.

Circuit/system Testing

Important: Circuit/System Verification must be performed before performing the Circuit/System Testing.

  1. Ignition OFF, disconnect the harness connector at the coolant level switch.
  2. Test for less than 5 ohms of resistance between the ground circuit terminal B and ground.
  3. Ignition ON, verify the scan tool coolant level switch parameter reads LOW.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool coolant level switch parameter reads OK.
  5. If all circuits test normal, test or replace the coolant level switch.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the coolant level switch.
  2. Test for infinite resistance between the signal terminal A and the ground circuit terminal B with the switch in the open position.
  3. Test for less than 5 ohms between the signal terminal A and the ground circuit terminal B with the switch in the closed position.

Repair Instructions

•Instrument Cluster Replacement
•Radiator Surge Tank Replacement
•Control Module References for ECM replacement, setup, and programming

Repair Verification

Verify that the low coolant indicator is OFF with the engine coolant at the proper level.

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