Temperature Sensor (Gauge): Testing and Inspection

Coolant Temperature Gauge Test
'99 model:
1. Check the No. 9 (7.5 A) fuse in the under-dash fuse/ relay box before testing.





2. Make sure the ignition switch is OFF, then disconnect the YEL/GRN wi7re (A) from the coolant temperature gauge sending unit (B), and ground it with a jumper wire.
3. Turn the ignition switch ON (II). Check that the pointer of the coolant temperature gauge starts moving toward the "H" mark. Turn the ignition switch OFF before the pointer reaches "H" on the gauge dial. Failure to do so may damage the gauge.
^ If the pointer of the gauge does not move at all, check for an open in the YEL/GRN wire. If the wires are OK, replace the coolant temperature gauge.
^ If the coolant temperature gauge works, test the coolant temperature gauge sending unit.

'00-03 models:
Coolant Temperature Gauge Needle Does Not Move at All:





1. Turn the ignition switch OFF, and connect powertrain control module (PCM) connector terminal A31 to body ground with a jumper wire.
2. Turn the ignition switch ON (II).
After 30 seconds or more, does the temperature gauge needle move to the Hot side?
YES-Substitute a known-good PCM and recheck. If the symptom/indication goes away, replace the original PCM.
NO-Go to step 3.
3. Turn the ignition switch OFF, and disconnect PCM connector A (32P).





4. Turn the ignition switch ON (II), and measure voltage between PCM connector terminal A31 and body ground.
Is there about 5 V?
YES-Replace the fuel and temperature gauge assembly.
NO-Go to step 5.





5. Turn the ignition switch OFF, and check for continuity between PCM connector terminal A31 and gauge assembly connector terminal B3.
Is there continuity?
YES-Replace the fuel and temperature gauge assembly.
NO-Repair open in the wire between PCM connector terminal A31 and gauge connector terminal B3.

Coolant Temperature Gauge Needle Goes Past the Hot Mark:
1. Turn the ignition switch OFF, and disconnect PCM connector A (32P).
2. Turn the ignition switch ON (II), and watch the coolant temperature gauge.
Does the temperature gauge need to move at all ? (you may have to watch it for about 30 seconds).
YES-Go to step 3.
NO-Substitute a known-good PCM and recheck. If the symptom/indication goes away, replace the original PCM.
3. Turn the ignition switch OFF, then turn it ON (II) again, and watch the coolant temperature gauge.
Does the temperature gauge needle immediately go past the Hot mark?
YES-Replace the fuel and temperature gauge assembly.
NO-The temperature gauge needle went past the Hot mark after about 30 seconds or more. Go to step 4.
4. Turn the ignition switch OFF, and disconnect the gauge assembly connector B (18P).





5. Check for continuity between PCM connector terminal A31 and gauge assembly connector terminal B3.
Is there continuity?
YES-Repair short in the wire between PCM connector A31 end gauge connector terminal B3.
NO-Replace the fuel and temperature gauge assembly.