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DTC P0118 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR HIGH VOLTAGE INPUT Honda Prelude V

Testing & Diagnostics 1 illustration ~667 words
  1. Turn ignition on. Using OBD-II scan tool, check ECT sensor. If -4°F (-20°C) or less is indicated, go to next step. If -4°F (-20°C) or less is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires between ECT sensor connector and PCM connector. See «WIRING DIAGRAMS»(ref-16355) article.
  2. Disconnect ECT sensor 2-pin connector. Connect a fused jumper wire between ECT harness connector terminals. Using OBD-II scan tool, check ECT sensor. If -4°F (-20°C) or less is indicated, go to next step. If -4°F (-20°C) or less is not indicated, replace ECT sensor.
  3. Turn ignition off. Connect a fused jumper wire between PCM 16-pin connector "D" terminal D2 (Red/White wire) and terminal D11 (Green/Black wire). see scheme 4 Turn ignition on. Using OBD-II scan tool, check ECT sensor. If -4°F (-20°C) or less is not indicated, repair open in wire(s) between ECT sensor and PCM connector terminals. See «WIRING DIAGRAMS»(ref-16355) article. If -4°F (-20°C) or less is indicated, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

Scheme 26

Scheme 26: DTC P0122 - THROTTLE POSITION (TP) SENSOR LOW VOLTAGE INPUT
Scheme 26: DTC P0122 - THROTTLE POSITION (TP) SENSOR LOW VOLTAGE INPUT
  1. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Turn ignition off. Turn ignition on. Using OBD-II scan tool, check throttle position. If reading is about 10 percent with throttle fully closed and 90 percent with throttle fully opened, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at TP sensor connector and PCM connector. See «WIRING DIAGRAMS»(ref-16355) article. If reading is not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor 3-pin connector. Turn ignition on. Measure voltage between TP sensor harness 3-pin connector terminal No. 1 (Green/Black wire) and terminal No. 3 (Yellow/Blue wire). see scheme 6 If about 5.0 volts does not exist, go to next step. If about 5.0 volts exists, go to step 4).
  3. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminal D10 (Yellow/Blue wire) and terminal D11 (Green/Black wire). see scheme 4 If about 5.0 volts exists, repair open in Yellow/Blue wire between PCM connector D10 and TP sensor. See «WIRING DIAGRAMS»(ref-16355) article. If about 5.0 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  4. Turn ignition off. Measure TP sensor resistance between terminals No. 1 and 2 with throttle fully closed. (Scheme 26) If resistance is about 500-900 ohms, go to next step. If resistance is not about 500-900 ohms, replace TP sensor.
  5. Measure TP sensor resistance between terminals No. 2 and 3 with throttle fully closed. (Scheme 26) If resistance is about 4500 ohms, go to next step. If resistance is not about 4500 ohms, replace throttle body (TP sensor is not serviced separately).
  6. Reconnect TP sensor connector. Turn ignition on. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminal D1 (Red/Black wire) and terminal D11 (Green/Black wire). see scheme 4 If about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. On vehicles equipped with A/T, if voltage is not as specified, go to next step. On vehicles equipped with M/T, if voltage is not as specified, repair short in Red/Black wire between PCM connector terminal D1 and TP sensor.
  7. Turn ignition off. Disconnect Transmission Control Module (TCM) 22-pin Gray connector "B". TCM is located in passenger footwell next to PCM. Turn ignition on. Using backprobe set, measure voltage between PCM 16-pin connector terminal D1 (Red/Black wire) and terminal D11 (Green/Black wire). If about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open exists, replace TCM. If voltage is not as specified, repair short in Red/Black wire between PCM connector terminal D1, TCM connector terminal B4, and TP sensor connector. See «WIRING DIAGRAMS»(ref-16355) article.

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