P0374 — Timing Reference High Resolution Signal A No Pulses

powertrain (engine/transmission)

Is it safe to drive?

Stop driving until P0374 is repaired P0374 indicates that a critical high-resolution timing signal is missing. Continued operation can cause stalling, no-start conditions, and loss of power, so the vehicle should not be driven normally until the signal and its cause are verified.

Typical symptoms

  • The engine cranks but will not start because the powertrain control module cannot synchronize injection and ignition timing.
  • The engine stalls suddenly or repeatedly, particularly during startup or at low speed.
  • P0374 remains stored in the powertrain control module and the check-engine light is illuminated.
  • The engine may run with a severe misfire, rough idle, hesitation, or a substantial loss of power if the missing pulses are intermittent.
  • Related crank or cam position codes may be present alongside P0374.

Common causes

  • A failed high-resolution timing-reference sensor, which may be a camshaft or crankshaft-reluctor position sensor depending on the engine design.
  • An open circuit, short to power or ground, or high resistance in the sensor output, supply, or ground wiring.
  • A corroded, loose, or water-contaminated sensor connector that interrupts the P0374 timing signal.
  • Excessive sensor air gap, a damaged reluctor wheel, or missing target teeth that prevent the sensor from producing pulses.
  • A fault inside the powertrain control module's high-resolution timing-reference input circuit.

How to diagnose with an OBD scanner

  1. Read P0374 and capture operating data Connect an OBD2 scanner such as ELM327 or AIScanAuto, retrieve stored and pending codes, and save freeze-frame data. Confirm whether P0374 occurs during cranking and note any related crank or cam position codes. A live-data PID, if supported, can help show whether the timing signal disappears under specific conditions.
  2. Locate and inspect the timing-reference circuit Use the service wiring diagram to identify the high-resolution timing-reference sensor rather than assuming it is the same sensor used for basic engine speed. Inspect its connector, wiring, routing, and sensor mounting for corrosion, looseness, chafing, or damage.
  3. Measure the actual sensor waveform Back-probe the sensor output while the engine is cranked and use an oscilloscope with the appropriate probe for the sensor type. A healthy sensor should produce a repeatable pulse train. No waveform confirms the no-pulse condition reported by P0374 and separates a signal failure from a stored-code-only complaint.
  4. Check power, ground, and signal integrity Verify sensor supply voltage, ground continuity, and output resistance against service specifications. Include any pull-up or pull-down circuit shown in the wiring diagram. Repair open or shorted wiring and clean or replace a damaged connector before condemning the sensor.
  5. Inspect the reluctor or timing target Check the crank or cam reluctor wheel for cracked sections, missing teeth, excessive runout, and impact damage. Confirm that the sensor-to-target air gap is within specification. Correct the gap, target damage, or related mechanical timing issue before continuing the electrical tests.
  6. Validate the repair and evaluate the control module After repair, clear P0374 with the scanner and repeat the crank, warm-up, and road test while checking for code return. If a verified-good sensor and sound wiring still produce no pulses, perform manufacturer-specific powertrain control module diagnostics rather than automatically replacing the module.

Approximate repair cost

Typical independent-shop estimates for P0374 are about $200-$1,200 for diagnosis and repair, including a sensor or wiring repair. A damaged reluctor or powertrain control module issue can push the cost above $1,000. These figures are estimates and vary by region.

Common questions

What exactly does P0374 mean?

P0374 means the powertrain control module received no pulses from the high-resolution timing-reference signal A circuit used to control precise ignition and fuel injection timing.

Can the vehicle be driven with P0374 stored?

No. P0374 can produce an intermittent or complete loss of engine synchronization, leading to stalling, rough operation, or a no-start condition while the vehicle is being driven.

Is the camshaft position sensor always the failed part?

Not necessarily. The high-resolution reference may come from a camshaft or crankshaft-related sensor, and P0374 can also result from damaged wiring, a bad connector, a reluctor defect, or a control-module input failure.

Can an ELM327 or AIScanAuto confirm the missing pulses?

It can confirm the P0374 code, related codes, and available freeze-frame data, but it generally cannot directly verify the sensor waveform. An oscilloscope test of the timing-reference signal is needed for that confirmation.

Your scan tool just displayed P0374, and now you're wondering what that means for your vehicle. This code falls under the powertrain category, which covers anything related to the engine and transmission control systems. The full technical description reads "Timing Reference High Resolution Signal A No Pulses" — a mouthful that essentially tells you the engine computer stopped receiving the high-speed timing signal it expects from a specific sensor circuit.

Modern engines rely on high-resolution signals to synchronize fuel injection, ignition timing, and in some cases transmission shift points. When the PCM (Powertrain Control Module) compares the incoming signal against its expected pattern and finds nothing but silence, it logs P0374 and illuminates the Check Engine light. The module also captures a freeze frame — a snapshot of operating conditions when the failure occurred. That snapshot records RPM, engine load, coolant temperature, and vehicle speed, which proves invaluable during diagnosis since it reveals exactly what the engine was doing when the problem surfaced.

Symptoms of P0374

When P0374 sets, you'll typically notice one or more of these conditions:

  • Check Engine light stays illuminated on the dashboard
  • Fuel consumption climbs noticeably in some vehicles
  • The related system runs inconsistently or stops working entirely
  • Engine performance drops or the car enters limp-home mode depending on which circuit failed
  • In rare cases, rough idle or hesitation during acceleration

Common Causes

The root cause usually traces back to one of these culprits:

  • Damaged or corroded connector at the sensor or PCM
  • Failed crankshaft position sensor, camshaft position sensor, or related actuator
  • Blown fuse protecting the circuit
  • Wiring harness damage from heat, chafing, or rodent intrusion
  • Faulty control module driver (less frequent but possible)

How to Diagnose P0374

Follow these steps to isolate the problem without replacing parts unnecessarily:

  1. Connect an OBD2 scanner and verify P0374 is stored, then record the freeze frame data — this shows what the engine was doing when the fault appeared.
  2. Check for any related diagnostic trouble codes. Correlated codes often point directly to the failing component.
  3. Inspect the affected circuit's wiring and connectors visually. Look for corrosion, broken insulation, bent pins, or anything that interrupts the signal path.
  4. Test reference voltage, ground integrity, and signal continuity at the sensor connector using a multimeter.
  5. Perform a wiggle test on the harness while monitoring live data. Any signal dropout during movement reveals an intermittent wire break.
  6. Clear the code and complete a full drive cycle under the conditions captured in the freeze frame. If P0374 returns, the fault is confirmed and not a one-time glitch.

Repair Options and Costs

Start with the simplest and least expensive possibilities before tackling major components:

  • Wiring harness repair or connector replacement — $80–$250
  • Sensor or actuator replacement — $150–$500
  • Control module diagnosis and repair — $300–$1,000

Total Repair Cost for P0374

Your actual expense hinges entirely on which part failed. At independent shop rates, expect to pay between $80 and $250 for wiring or connector work, $150 to $500 for a new sensor or actuator, and $300 to $1,000 if the PCM itself requires attention. Always confirm the root cause with proper testing before purchasing components — the priciest scenario is rarely where you should start.

Can You Drive with P0374?

This code typically doesn't leave you stranded. Your vehicle usually remains drivable, though you may experience diminished performance or reduced functionality of an associated system. Treat the situation as urgent if the engine stalls, fails to start, or if you notice brake assist or power steering warnings.

Related OBD2 Codes