P0372
Timing Reference High Resolution Signal A Too Few PulsesP0372 is a generic OBD-II powertrain diagnostic trouble code: Timing Reference High Resolution Signal A Too Few Pulses. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0372 means
P0372 — "Timing Reference High Resolution Signal 'A' Too Few Pulses" — is stored when the Powertrain Control Module (PCM) counts fewer pulses in the high-resolution engine position signal than expected for the number of crankshaft revolutions that have occurred. The high-resolution timing reference is a dense, equally-spaced pulse train generated by a reluctor ring (tone wheel) attached to the crankshaft or camshaft; it gives the PCM cycle-by-cycle precision for ignition timing advance, variable cam phaser control, and fuel injection timing on platforms such as Ford EEC-IV/EEC-V, GM 6.5L Stanadyne diesel, certain Honda DOHC, and BMW high-precision phaser systems.
The PCM compares the actual pulse count against the expected count for a given crank interval. When the observed count falls short — but pulses are still arriving — the fault is specifically P0372 rather than a complete loss (P0374). Typical causes are a damaged reluctor ring with missing or worn teeth, a sensor air gap that is too large causing the sensor to miss low-amplitude signal peaks, or a Hall-effect element blocked by metallic contamination. Unlike the intermittent variant (P0373), P0372 represents a consistent undercount, meaning the deficiency is repeatable across multiple engine cycles.
Driveability impact ranges from rough idle and hesitation to intermittent misfires and, in severe cases, stalling. The engine rarely reaches a complete no-start on P0372 alone, but extended cranking may occur because the PCM cannot accurately establish TDC on every cycle. Repair begins with a visual inspection of the reluctor ring and sensor air gap before condemning the sensor itself.
Common causes
Most-frequently reported root causes when P0372 is logged.
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1
Damaged, cracked, or corroded reluctor ring (tone wheel) with missing or worn teeth producing a reduced pulse count.
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2
Excessive sensor air gap — sensor mounted too far from the reluctor ring causing low-amplitude signals that the PCM circuit fails to register.
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3
Hall-effect sensor element contaminated with metallic debris or oil sludge choking the signal output.
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4
Open or high-resistance condition in the sensor signal wire causing intermittent pulse loss.
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5
Corroded or loosely seated connector at the crankshaft or camshaft position sensor.
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6
Timing belt or chain wear causing slight ring displacement and altered pulse timing that undercuts the expected count.
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7
Faulty PCM input circuit on the high-resolution signal channel.
Symptoms drivers notice
How to diagnose P0372
A typical diagnostic flow when this code is present.
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1
Connect an OBD-II scan tool and record all stored and pending codes, noting any concurrent P0373, P0374, or cam/crank sensor codes that indicate a related fault.
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2
Inspect the reluctor ring (tone wheel) visually for cracked, missing, bent, or heavily corroded teeth — a flashlight and mirror or borescope may be needed.
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3
Check the crankshaft or camshaft position sensor air gap with a feeler gauge and compare to the manufacturer's specification (typically 0.5–1.5 mm depending on platform).
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4
Inspect the sensor body and connector for oil contamination, metallic debris buildup, and mechanical damage.
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5
Measure supply voltage (5V reference), ground integrity, and signal circuit continuity at the sensor connector with a digital multimeter.
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6
Use an oscilloscope on the signal wire during cranking to observe the pulse train — a healthy high-resolution signal should show an even, dense square wave; missing pulses appear as wider gaps in the pattern.
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7
If the reluctor ring and air gap are within spec and the sensor signal shows consistent dropouts, replace the position sensor and retest.
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8
Verify timing belt/chain condition if the code accompanies cam timing faults.
Related powertrain codes
Frequently asked questions
What is the difference between P0372, P0373, and P0374?
All three relate to the high-resolution timing reference signal on channel A. P0372 means the pulse count is consistently too low (missing teeth or large air gap). P0373 means the pulses are arriving but erratically or intermittently. P0374 means no pulses are detected at all, which is the most severe condition and typically causes a no-start.
Can a dirty or contaminated sensor cause P0372 without the sensor being broken?
Yes. Hall-effect sensors are susceptible to metallic contamination from worn engine components. A buildup of fine iron particles on the sensor tip can partially obstruct the magnetic field, causing the sensor to miss weak pulses from the reluctor ring. Cleaning the sensor tip and the surrounding area sometimes resolves P0372 without replacement.
Which platforms are most affected by P0372?
P0372 appears most frequently on Ford EEC-IV/EEC-V platforms, GM 6.5L Stanadyne diesel applications, and BMW engines with high-precision camshaft phaser systems that rely on a dense reluctor ring for phaser position feedback. Honda DOHC engines using dual high-resolution references also set this code.
Is P0372 an emissions-related fault?
Yes — timing reference faults degrade ignition and fuel delivery precision, which increases raw emissions. In jurisdictions using OBD-II readiness checks, P0372 will illuminate the MIL and cause an emissions test failure.
Disabling P0372 in software
RaceTune can permanently disable P0372 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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