The coolant temperature information is conveyed to the instrument panel, through the PCM, from the Engine Coolant Temperature (ECT) sensor. To test and remove the sensor, refer to Emission Controls . To test the gauge, perform the following testing procedure.
See Figure 1
- Check that the No.1 fuse (10 A) has continuity before testing.
- With the ignition switch OFF , disconnect the yellow/green wire from the gauge sending unit. Then ground it to a place on the engine block (or other known good ground) with a jumper wire.
- Turn the ignition switch to the ON position.
- Watch the Engine Coolant Temperature (ECT) gauge as it should start moving towards the hot ("H") mark.
- If the pointer does not move at all or moves erratically, check for an open or point of high resistance in the yellow/green wire. If the wires check out OK, replace the gauge.
- The sending unit should be the next component tested if the above steps did not reveal the problem.
- Test the sending unit by disconnecting the yellow/green.
- Connect an ohmmeter to the positive terminal on the sending unit and a good known ground on the engine block.
- The resistance should be 137 ohms at a temperature of 133°F (56°C). If the engine is hot, and has a temperature of 185-212°F (85-100°C ), the resistance should be 46 ohms-30 ohms.
REMOVAL & INSTALLATION
- Locate the engine coolant sending unit on the engine.
- Remove the negative battery cable.
- Disconnect the sending unit electrical harness.
- Drain the engine coolant to a level below the unit.
- Remove the Engine Coolant Temperature (ECT) sending unit using a pressure switch socket or wrench.
- Coat the threads of the sending unit with a suitable sealant. Make sure the sealant is safe for use on sending units and will not impede proper temperature readings.
- Install the new sensor and tighten to 7 ft. lbs. (10 Nm) using a wrench or sending unit pressure switch socket..
- Refill the engine with Acura/Honda approved or equivalent coolant.
The Powertrain Control Module (PCM) idle memory must be reset after reconnecting the battery. Start the engine and hold it at 3000 rpm until the cooling fan comes on. Then allow the engine to idle for about five minutes with all accessories OFF and with the transmission in Park or Neutral.
- Reconnect the negative battery cable.
- Start the engine, allow it to reach operating temperature and check for leaks.