Timing Reference High Resolution Signal A Too Many Pulses
The PCM detected too many pulses from the engine position sensor (timing reference signal A), indicating the sensor is producing an abnormal signal pattern. This disrupts the engine's ability to accurately determine crankshaft position and timing, which can affect ignition timing and fuel injection.
What You Might Notice
- Check Engine Light illuminated
- Engine hesitation or stumbling during acceleration
- Rough idle or stalling
- Reduced fuel economy
- Difficulty starting the engine
Most Common Causes
- 1
Faulty crankshaft position sensor
The sensor may be failing and producing excessive signal pulses, or have internal electrical faults causing erratic readings.
- 2
Damaged reluctor wheel or tone ring
Chips, cracks, or corrosion on the reluctor ring can cause the sensor to read multiple pulses as it passes damaged teeth, creating signal anomalies.
- 3
Wiring problems or poor connections
Corroded terminals, loose connectors, or damaged wiring to the position sensor can generate intermittent or multiplied signal pulses.
- 4
Engine oil contamination or bearing wear
Contaminated oil can affect sensor operation, and excessive bearing wear may allow the crankshaft to move abnormally, causing sensor signal distortion.
How to Diagnose It
- 1
Check Faulty crankshaft position sensor — The sensor may be failing and producing excessive signal pulses, or have internal electrical faults causing erratic readings.
- 2
Check Damaged reluctor wheel or tone ring — Chips, cracks, or corrosion on the reluctor ring can cause the sensor to read multiple pulses as it passes damaged teeth, creating signal anomalies.
- 3
Check Wiring problems or poor connections — Corroded terminals, loose connectors, or damaged wiring to the position sensor can generate intermittent or multiplied signal pulses.
- 4
Check Engine oil contamination or bearing wear — Contaminated oil can affect sensor operation, and excessive bearing wear may allow the crankshaft to move abnormally, causing sensor signal distortion.
How to Fix It
- 1
Inspect and replace crankshaft position sensor
Locate the sensor on the engine block, test it with an oscilloscope to confirm excessive pulse output, then replace the faulty sensor with a new OEM or quality equivalent unit.
- 2
Check and clean wiring connections
Inspect the sensor wiring harness for corrosion, damage, or loose connectors. Clean corroded terminals with electrical contact cleaner and ensure tight connections to eliminate signal interference.
- 3
Inspect reluctor wheel for damage
Remove the timing cover or access the reluctor ring to visually inspect for cracks, chips, or missing teeth. If damaged, replace the crankshaft or timing component depending on the vehicle design.
- 4
Change engine oil and filter
Replace the engine oil and filter with the manufacturer's recommended grade. If contamination is severe or bearings are worn, have a mechanic perform a compression test to assess engine condition.
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