5-Faulty Engine Speed Signal

DIAGNOSIS
- Faulty engine control module or harness
- Faulty PCM (Power Steering Control Module)

SYMPTOM
- Engine operation is controlled only by vehicle speed sensor 2.





1. Check engine rpm input signal at PCM.





a. Connect oscilloscope between PCM and GND. (DC COUP, 0.5 V/Piv, 5 ms/Div, x 10 probes)
b. Turn ignition switch "ON."
c. Start engine.





d. Observe waveform pattern shown on oscilloscope screen. Connector & Terminal/Specified voltage: (R91) No. 3 - Body/0 - 10 V

2. Check and repair engine control module and engine rpm signal harness.
a. Turn ignition switch "OFF."
b. Disconnect PCM from connectors.
c. Disconnect engine control module from connectors.





d. Measure resistance between PCM connector and engine control module connector terminals indicated below. Connector & Terminal/Specified resistance:
- (R91) No. 3-(B59) No. 64/1 ohm. or less
- (R91) No. 3-Body/1 M ohm, or more