Reluctor/Crankshaft Sensor Checks: Overview
Scope AnalysisDiscovery has sealed connectors. Probe carefully around the outside of the seal.
1. Backprobe terminal 12 of ECM connector 1033 to observe waveform of crankshaft sensor signal.
2. Start engine and allow it to idle.
3. Use handheld scope or use TestBook Uniscope function. Set scope to 2 ms. time base and 15 volt range, and record.
4. Observe wave pattern produced by sensor (normal pattern shown in figure 10 of Operation Pride Manual). If reluctor and pickup are in good condition, all 35 should have approximately the same amplitude with a slight displacement in the positive x-direction.
(Alternative method: Set scope to 2ms/25v scale and raise RPM until 2 missing tooth patterns are seen. Freeze scope image.)
5. Position scope measurement pointers on the peak of an average high positive wave form, and on the peak of the lowest(and/or highest) positive wave form. The peaks of the positive going voltages should be within 20% of each other (i.e. with a 7.95 volt average amplitude, lowest voltage should be 6.36, highest 9.54)
6. See figure 11 of Operation Pride Manual for examples of various reluctor tab problems.
7. If a problem is observed, note the position of the abnormal waveform tooth in relation to the missing tooth to enable easy location when checking reluctor ring.