P0373 medium Severity

P0373: Timing Reference High Resolution Signal A Intermittent/Erratic Pulses

Engine performance issues such as rough idle, decreased power, hard starting, or stalling may occur.

Overview

P0373 indicates that the engine control module (PCM/ECM) has detected intermittent or erratic high-resolution timing reference signal 'A' from position sensors, often tied to the crankshaft position sensor circuit and affecting engine timing.

Common Symptoms

  • Check Engine Light illuminated
  • Hard starting or no start
  • Rough idle or engine hesitation
  • Loss of engine power or stalling

Most Common Causes

Faulty crankshaft position sensor or high‑resolution timing reference sensor high

Sensor produces erratic or intermittent pulses that disrupt timing reference.

Damaged wiring or poor connections in the timing reference signal circuit high

Frayed wires, corrosion, or loose connectors cause intermittent signal loss.

Reluctor wheel damage or contamination medium

Damaged or dirty tone wheel behind sensor can disturb signal patterns.

Faulty engine control module (ECM/PCM) low

ECM internal fault or processing issue leading to misinterpretation of signals.

Electromagnetic interference affecting signal integrity low

Aftermarket electrical accessories or alternator noise can distort pulses.

Diagnostic Steps

  1. Scan vehicle with OBD‑II scanner to confirm P0373 and note any related codes.
    Expected: P0373 present, possibly with other timing or sensor codes.
    Interpretation: Confirms intermittent/erratic timing signal events logged by PCM.
  2. Visually inspect crankshaft/camshaft position sensor wiring and connectors.
    Expected: Look for damaged insulation, corrosion, loose pins.
    Interpretation: Wiring damage can cause intermittent signal loss triggering code.
  3. Test sensor output with multimeter or oscilloscope while cranking engine.
    Expected: Steady, consistent waveform pulses; variation indicates fault.
    Interpretation: Erratic or weak waveform identifies sensor or tone ring issues.
  4. Inspect reluctor wheel/tone ring for physical damage or contamination.
    Expected: Check ring teeth integrity and cleanliness.
    Interpretation: Damaged or dirty ring disrupts high‑resolution signal pulses.
  5. Check ECM reference voltage and ground at sensor connector.
    Expected: Stable reference voltage (often 5V) and good ground continuity.
    Interpretation: Lack of proper reference indicates wiring or module issue.

Repair Solutions

Replace faulty crankshaft position or high‑resolution sensor medium
Estimated Cost: $150 - $350

Sensor replacement often resolves intermittent timing signal issues.

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $200

Ensures stable signal communication between sensor and PCM.

Clean or repair reluctor wheel/tone ring medium
Estimated Cost: $80 - $250

Removes interference source for sensor signal generation.

Reprogram or replace ECM/PCM hard
Estimated Cost: $400 - $1200

Consider only if diagnostics confirm module fault.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming only sensor replacement without checking wiring or sensor signal integrity.

Frequently Asked Questions

What does a P0373 diagnostic trouble code signify?

Timing Reference High Resolution Signal A Intermittent/Erratic Pulses is the standard definition for P0373. This diagnostic code is triggered when the ECU detects a problem in the Ignition.

Can P0373 cause engine damage?

With a severity level of medium, engine performance issues such as rough idle, decreased power, hard starting, or stalling may occur.

What are the symptoms of P0373?

Common symptoms include: Check Engine Light illuminated, Hard starting or no start, Rough idle or engine hesitation. You might also notice the Check Engine Light is on.

Potential causes for OBDII code P0373

Potential culprits include: Faulty crankshaft position sensor or high‑resolution timing reference sensor, Damaged wiring or poor connections in the timing reference signal circuit, Reluctor wheel damage or contamination. A proper diagnosis is recommended.

Repair cost breakdown for P0373

It depends on what needs to be fixed. Repair or replace damaged wiring/connectors repairs are cheaper (~$200), while Reprogram or replace ECM/PCM repairs are on the higher end (~$1200).

Is the P0373 code specific to Nissan?

This is a universal code. You might see P0373 on Ford, Chevrolet, Toyota, Honda, Nissan, or any other OBD-II vehicle.

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