Timing Reference High Resolution Signal B Malfunction
The PCM detected a malfunction with the high resolution timing reference signal B, typically from the camshaft or crankshaft position sensor. This signal is critical for precise engine timing and fuel injection control, and its failure will degrade engine performance and fuel economy.
What You Might Notice
- Check Engine Light illuminated
- Rough idle or unstable engine running
- Reduced fuel economy
- Engine hesitation or stumbling during acceleration
- Difficulty starting the engine
Most Common Causes
- 1
Faulty camshaft or crankshaft position sensor
The sensor itself has failed electrically or mechanically, preventing proper signal transmission to the PCM.
- 2
Damaged wiring or loose connectors
Corroded, broken, or disconnected wires in the sensor circuit prevent clean signal delivery to the engine control module.
- 3
Contaminated or damaged reluctor ring
Metal debris, oil accumulation, or physical damage to the timing wheel or reluctor ring disrupts the magnetic signal generation.
- 4
Engine control module (PCM) failure
In rare cases, the PCM circuit dedicated to processing the timing signal has failed or developed an internal fault.
How to Diagnose It
- 1
Check Faulty camshaft or crankshaft position sensor — The sensor itself has failed electrically or mechanically, preventing proper signal transmission to the PCM.
- 2
Check Damaged wiring or loose connectors — Corroded, broken, or disconnected wires in the sensor circuit prevent clean signal delivery to the engine control module.
- 3
Check Contaminated or damaged reluctor ring — Metal debris, oil accumulation, or physical damage to the timing wheel or reluctor ring disrupts the magnetic signal generation.
- 4
Check Engine control module (PCM) failure — In rare cases, the PCM circuit dedicated to processing the timing signal has failed or developed an internal fault.
How to Fix It
- 1
Inspect and test the position sensor
Use a multimeter and oscilloscope to test sensor voltage and signal waveform; replace the sensor if readings are out of specification.
- 2
Check and repair wiring and connectors
Visually inspect the sensor wiring harness for corrosion, damage, or loose connections; repair or replace as needed and ensure proper seating at the PCM connector.
- 3
Inspect the reluctor ring or timing wheel
Remove and examine the reluctor ring or camshaft timing wheel for metal debris, debris buildup, or physical damage; clean or replace if necessary.
- 4
Replace the PCM if all components test good
If sensor, wiring, and reluctor ring are confirmed functioning normally, the PCM itself may need replacement; consult a dealer for PCM reprogramming.
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