P0374 Code - Timing Reference High Resolution Signal 'A' No Pulses
Quick Answer
The P0374 code indicates that there are no pulses detected in the Timing Reference High Resolution Signal 'A'. Common causes include Faulty crankshaft position sensor, Faulty camshaft position sensor, Damaged wiring or connectors in the signal circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0374 indicates Timing Reference High Resolution Signal 'A' No Pulses.
- Common causes
- Common causes include Faulty crankshaft position sensor, Faulty camshaft position sensor, Damaged wiring or connectors in the signal circuit.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0374 Description
The P0374 code indicates that there are no pulses detected in the Timing Reference High Resolution Signal 'A'. This signal is crucial for the proper timing of the engine's combustion process, which directly impacts the vehicle's performance. Without this signal, the engine may misfire, have difficulty starting, or experience a lack of power. This code typically points to a fault in the crankshaft position sensor, camshaft position sensor, or the wiring/connectors associated with these components. Ignoring this issue can lead to further damage to the engine, reduced fuel efficiency, and potential stalling while driving.
Common Causes of P0374
- Faulty crankshaft position sensor
- Faulty camshaft position sensor
- Damaged wiring or connectors in the signal circuit
- Issues with the engine control module (ECM)
- Timing belt or chain alignment issues
Symptoms of P0374
- Engine misfires
- Difficulty starting the engine
- Reduced power or acceleration
- Engine stalling
- Check Engine Light illuminated
How to Fix P0374
- Perform a thorough inspection of the timing reference signal circuit and associated components.
- Test the crankshaft and camshaft position sensors for proper operation.
- Check the wiring and connectors for any damage or corrosion, repair or replace as needed.
- Reset the fault codes and monitor the system to ensure the issue has been resolved.
- If necessary, replace the faulty sensors or components to restore proper timing signal.
Cost to Fix P0374
The cost of repairing a P0374 code can vary depending on the specific cause of the issue. In general, the replacement of a crankshaft or camshaft position sensor can range from $50 to $200 each, while the cost of wiring repairs or an ECM replacement can add to the total cost. Labor costs can also vary, with hourly rates typically ranging from $80 to $150. It is recommended to consult with a qualified mechanic or repair shop for a more accurate estimate based on your vehicle's make and model.
When is the Code Detected?
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Code P0374 Information for Specific Makes
- P0374 Mercedes-Benz — Timing Reference High Resolution Signal 'A' No Pulses
Frequently Asked Questions about P0374 Code
No Frequently Asked Questions about P0374 Code found.
Discuss the causes and fixes for P0374 OBDII Code
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Jan 2026, 2004 3500 Duramax Diesel, LLY 131,000 mi. pulled code P0374 after 45 minutes idling engine symbol appeared. Cut truck off, tried starting it, it shut right off, tried two more times same result. Grabbed OBD scanner, Got P0374 & P0700 codes. Cleared them. It started right up. Drove Next day replaced with New primary battery. Stopped at Diesel repair shop, they confirmed that might have been the problem, it should be fine now.
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On the LLY Duramax, P0374 means the ECM lost the high-resolution timing signal from the injection pump / crank reference. When that signal drops out, the engine will usually stall or start and die exactly like you described. The P0700 just means the transmission module saw a major engine fault and flagged it.
Low system voltage can absolutely trigger this. These trucks are very sensitive to battery condition, especially after long idle time. If voltage drops or gets noisy, the ECM can lose the timing signal even though the sensor itself is fine. Replacing a weak battery was a good move.
That said, I’d treat it as “possibly fixed,” not guaranteed fixed yet.
If the batteries were mismatched, old, or one was dragging the other down, that can cause intermittent voltage dips. On a Duramax you really want both batteries healthy and matched. Also check:
• Both battery cables and grounds (frame + engine grounds)
• The junction block connections
• Alternator output under load
• Harness near the crank / pump sensor for rubbing or oil contaminationIf it was purely voltage-related, the truck will run normally and the code won’t return. If P0374 comes back, then you’d start suspecting the crank reference wiring or sensor circuit.
For now, drive it and monitor. One event after a long idle with a weak battery is believable. Repeated events mean you dig deeper.
The key thing: you did the right first repair. Just keep an eye on it.
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