P0376

Timing Reference High Resolution Signal B Too Many Pulses

P0376 is a generic OBD-II powertrain diagnostic trouble code: Timing Reference High Resolution Signal B Too Many 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.

Code
P0376
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
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What P0376 means

P0376 — "Timing Reference High Resolution Signal 'B' Too Many Pulses" — is stored when the PCM counts more pulses in the high-resolution channel B signal than expected for the number of crankshaft revolutions completed. On platforms equipped with a dual high-resolution reference system, the PCM independently counts the pulse rate from each channel and validates both against the known tooth count of the respective reluctor ring. When channel B delivers an excess pulse count, the PCM's crank position calculation for that channel becomes corrupted, which can cause timing errors on the cylinder bank or camshaft axis associated with channel B.

Too many pulses typically originate from one of three sources: electrical interference coupling extra transitions onto the signal line (noise spikes the PCM counts as legitimate teeth), a reluctor ring with physical damage that creates extra edges as a cracked or delaminated section flexes past the sensor, or a sensor air gap that is too small causing over-sensitivity to ring surface texture variations. The channel B architecture mirrors channel A — P0376 is the channel B counterpart to P0371 (channel A too many pulses) — so the same diagnostic principles apply, just applied to the secondary sensor circuit.

Symptoms are similar to other high-resolution signal faults: rough idle, cam phaser irregularity, and potential misfires. Hard no-start is less common on P0376 because channel A typically remains valid and provides primary crank position data, but on platforms where channel B is required for direct injection phasing or exhaust cam control, performance degradation can be significant. Oscilloscope analysis is the most reliable tool for confirming extra pulse edges in the channel B waveform.

Common causes

Most-frequently reported root causes when P0376 is logged.

  • 1
    Electrical noise or EMI coupling extra voltage transitions onto the channel B signal wire, interpreted by the PCM as additional teeth.
  • 2
    Damaged or cracked reluctor ring on the channel B axis — a delaminating or split tooth creates extra signal edges per revolution.
  • 3
    Sensor air gap too small on the channel B sensor, causing over-sensitivity to minor surface irregularities on the reluctor ring.
  • 4
    Corroded or damaged shielding on the channel B signal wiring allowing external interference ingress.
  • 5
    Failing alternator generating AC ripple that superimposes noise onto the sensor signal line.
  • 6
    Aftermarket accessory or high-current device near the channel B wiring inducing EMI.
  • 7
    Faulty channel B sensor with internal noise on the output signal.
  • 8
    Damaged sensor mounting causing physical contact between the sensor tip and the reluctor ring, generating friction-induced pulses.

Symptoms drivers notice

MIL / Check Engine Light illuminates.
Rough idle or irregular combustion from corrupted cam or crank position data on channel B.
Erratic or over-active variable cam phaser response on the cylinder bank associated with channel B.
Intermittent misfires attributed to timing inaccuracy.
Hesitation or stumble during acceleration.
Possible torque reduction or limp mode on platforms that enforce strict channel B validation.
No-start is uncommon unless channel A is simultaneously degraded.

How to diagnose P0376

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all stored codes; note P0375 (channel B general), P0377 (channel B too few), or P0371 (channel A too many) codes that suggest whether the excess-pulse issue is isolated to channel B or system-wide.
  2. 2
    Inspect the channel B sensor air gap and adjust to manufacturer specification if it is abnormally tight — excessive proximity to the ring surface increases sensitivity to debris and ring imperfections.
  3. 3
    Examine the channel B reluctor ring for cracked, delaminating, or split teeth that could generate double edges per tooth as the crack flexes during rotation.
  4. 4
    Inspect the channel B signal wiring for proximity to high-current cables (alternator output, power steering), sharp bends, or damaged shielding.
  5. 5
    Measure alternator AC ripple output (should be below 0.5V AC); a failing alternator is a common source of electrical noise on sensor signal lines.
  6. 6
    Use an oscilloscope on the channel B signal wire at idle and during acceleration — extra pulses appear as additional narrow spikes between expected tooth edges in the waveform.
  7. 7
    Reroute or shield the channel B signal wiring if EMI is confirmed; repair or replace the sensor if the extra pulses originate from the sensor itself.
  8. 8
    Replace the channel B sensor if the wiring and ring are intact and the oscilloscope confirms internally generated noise pulses.

Related powertrain codes

Frequently asked questions

What causes too many pulses vs too few pulses on the channel B signal?

Too few pulses (P0377) typically come from missing or worn reluctor ring teeth, a large air gap, or a contaminated sensor. Too many pulses (P0376) typically originate from electrical noise creating phantom transitions, a cracked ring tooth creating extra edges, or a sensor air gap that is too small. Both fault types corrupt the PCM's position calculation but from opposite directions.

Is P0376 on channel B the same as P0371 on channel A?

Structurally identical — P0376 is the channel B counterpart to P0371 (channel A too many pulses). The hardware layout, signal processing, and diagnostic approach are the same; only the physical sensor and PCM input pin location differ. If both P0371 and P0376 are present simultaneously, a shared electrical noise source such as a failing alternator is the most likely cause.

Can a failing alternator cause P0376?

Yes. AC ripple from a failing alternator is one of the most common sources of extra pulses on Hall-effect sensor signal lines. The noise superimposes onto the signal, creating extra transitions that the PCM counts as teeth. Measuring AC ripple at the battery with the engine running (threshold: less than 0.5V AC) is a worthwhile early step when wiring and sensor appear sound.

Which platforms most commonly set P0376?

P0376 is most frequently seen on Ford EEC-V modular engine applications, BMW engines with dual high-resolution camshaft phaser encoders, and certain GM diesel platforms using dual crankshaft or camshaft pickup circuits. It is not encountered on vehicles that only implement a single high-resolution reference channel.

Disabling P0376 in software

RaceTune can permanently disable P0376 — 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.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

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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