P0374
Timing Reference High Resolution Signal A No Pulses
Encountering the engine check light code P0374 signifies an explicit mechanical or electrical operational breakdown categorized as "Timing Reference High Resolution Signal A No Pulses". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
Code P0374 means your vehicle detected a problem with the timing reference high resolution signal a no pulses system. Typical symptoms include engine cranks but will not start, no tach signal. This is a serious fault — avoid extended driving and have your vehicle inspected by a mechanic as soon as possible to prevent further damage.
Symptoms
Engine cranks but will not start, no tach signal
Common Causes
- Dead high resolution sensor
- Unplugged connector
- Severed wiring harness
- Failed PCM
How to Fix
- 1 Replace high resolution sensor
- 2 Plug in connector securely
- 3 Repair cut wires
- 4 Test and replace PCM
Technical Explanation
Code P0374 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
An active P0374 code under high-severity conditions means the affected system is operating outside safe parameters. Continued driving — especially under load or at highway speeds — significantly increases the risk of secondary damage to components like unplugged connector.
Mechanic's Pro Tip
The most common mistake with P0374 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Related Fault Codes
Frequently Asked Questions
What does OBD2 code P0374 mean?
OBD2 code P0374 refers to Timing Reference High Resolution Signal A No Pulses. Encountering the engine check light code P0374 signifies an explicit mechanical or electrical operational breakdown categorized as "Timing Reference High Resolution Signal A No Pulses". Professional scanner tools usually flag this subsystem loop early on.
What are the most common symptoms of DTC P0374?
Drivers experiencing code P0374 typically report: Engine cranks but will not start, no tach signal.
Is it safe to drive with trouble code P0374 active?
An active P0374 code under high-severity conditions means the affected system is operating outside safe parameters. Continued driving — especially under load or at highway speeds — significantly increases the risk of secondary damage to components like unplugged connector.
How much does it cost to fix code P0374?
The estimated repair cost for P0374 ranges from $100 to $450 USD. Sensor replacement: 150 - 400
Sensor replacement: 150 - 400
Need Professional Diagnostic Assistance?
Always verify sensor signals and wiring integrity with an OBD2 scanner before purchasing replacement parts.
Explore All Powertrain Codes →