Test C: Malfunction In Water Temperature Receiver Gauge
WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Read the value of the hand-held tester:
- Check the output of the ECM. See Fig 1. Connect the hand-held tester to DLC3. See Figure. Turn the ignition switch to ON and push the hand-held tester main switch to ON. Select the item COOLANT TEMP in the DATA LIST and read it's value displayed on the hand-held tester.
- It is OK if the results are the same as the actual engine coolant temperature. If the results are OK, go to the next step. If the results are not OK, go to SELF-DIAGNOSTICS - ES300 article under FAULT ISOLATION in ENGINE PERFORMANCE.
- Check the combination meter assembly:
- Check the input signal of the waveform using an oscilloscope. Remove the combination meter assembly with the connectors still connected. Connect the oscilloscope to the terminals No. C7-11 and C7-1 of the combination meter assembly. See Figure. Start the engine. Check the signal waveform. See Fig 2. See TERMINALS C7-11 & C7-1 SIGNAL WAVEFORM table.TERMINALS C7-11 & C7-1 SIGNAL WAVEFORM
Item Contents Tool Setting 5 V/ DIV, 100 ms/ DV Vehicle Condition Engine Idle Speed - If the results are OK, check and replace the combination meter assembly. See COMBINATION METER SAFETY PAD SUB-ASSEMBLY under REMOVAL & INSTALLATION. If the results are not OK, repair or replace the harness or connector.
- Check the input signal of the waveform using an oscilloscope. Remove the combination meter assembly with the connectors still connected. Connect the oscilloscope to the terminals No. C7-11 and C7-1 of the combination meter assembly. See Figure. Start the engine. Check the signal waveform. See Fig 2. See TERMINALS C7-11 & C7-1 SIGNAL WAVEFORM table.