PCM Input Signals
- Timing control and triggering of fuel injectors are based on input signals from TDC/CRANK/CYL sensors. These sensors are Permanent Magnet (PM) generator pick-up coils.
- Using a DVOM (preferably with bar-graph function) on low-volt scale, test each sensor for pulse voltage signal at indicated PCM harness terminals while engine is cranking. See PCM INPUT SIGNAL & RESISTANCE TEST TERMINALS . If pulse signal is present, sensor is okay. If pulse signal is not present, go to next step.
- Turn ignition off. Unplug PCM connector. Inspect wiring harness and connectors. Measure resistance of each sensor at indicated PCM harness terminals. See PCM INPUT SIGNAL & RESISTANCE TEST TERMINALS . If resistance is within specification, go to next step. If resistance is not within specification, go to step 5).PCM INPUT SIGNAL & RESISTANCE TEST TERMINALS
Application PCM Terminals (1) Ohms CRANK B15 & B16 350-700 Ohms CYL B11 & B12 350-700 Ohms TDC B13 & B14 350-700 Ohms (1) See Fig 1. - Test each terminal for continuity to ground. If continuity exists, unplug sensor connector, and again test appropriate PCM terminal for continuity to ground. If continuity still exists, repair short to ground in harness. If continuity does not exist, replace sensor.
- Unplug sensor connector. Measure resistance of sensor. See Fig 2, 11, or 12. If resistance is within specification, repair open, short, or poor connection in sensor harness between PCM and sensor. See PCM INPUT SIGNAL & RESISTANCE TEST TERMINALS . If sensor resistance is not within specification, replace sensor assembly.