What Does P0374 Mean?
The ECM has detected intermittent or erratic pulses from the high-resolution timing reference signal A, which is a secondary fault qualifier for the crankshaft position sensor circuit. This indicates the sensor signal is cutting in and out rather than being completely absent. Symptoms include intermittent stalling, rough idle, hesitation during acceleration, and possible hard starting conditions.
Safety Warning
Intermittent CKP signal loss can cause unexpected engine stalling without warning. This is especially dangerous at highway speeds where loss of engine power means reduced braking and steering assistance. Repair before continued driving; if driving is necessary, avoid high-speed roads.
Common Causes
35%
Intermittent crankshaft position sensor failure due to heat-related internal component breakdown
30%
Wiring harness damage near exhaust components causing intermittent opens or shorts when hot
20%
Corroded or loose connector pins at the CKP sensor or ECM
10%
Reluctor wheel runout or debris causing inconsistent pulse pattern
5%
Electromagnetic interference from aftermarket ignition components or poor shielding
Diagnostic Steps
1
Monitor RPM PID and CKP signal data while driving under various conditions (cold start, hot idle, acceleration, deceleration) to identify when the erratic signal occurs.
2
Perform a thorough visual inspection of the CKP sensor wiring, looking for heat damage from nearby exhaust manifold or catalytic converter contact. Check for brittle insulation or melted wire loom.
3
Capture CKP waveform with a dual-channel oscilloscope while wiggle-testing the harness at multiple points. Look for signal dropouts or amplitude changes that correlate with wire manipulation.
4
With the engine off, perform a key-on resistance test of the CKP circuit from the ECM connector back to the sensor. Compare cold vs. hot resistance readings using a heat gun to simulate operating temperature.
5
Inspect the reluctor wheel for accumulated metallic debris (common with magnetic CKP sensors) and verify the tone ring is securely pressed onto the crankshaft or flexplate with no wobble.
Estimated Repair Cost
$80 - $500
Parts + labor, varies by vehicle and location
The ECM has detected intermittent or erratic pulses from the high-resolution timing reference signal A, which is a secondary fault qualifier for the crankshaft position sensor circuit. This indicates the sensor signal is cutting in and out rather than being completely absent. Symptoms include interm...
The most common cause of P0374 (Timing Reference High Resolution Signal A Intermittent/Erratic Pulses) is: Intermittent crankshaft position sensor failure due to heat-related internal component breakdown
Typical repair costs for P0374 range from $80 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent CKP signal loss can cause unexpected engine stalling without warning. This is especially dangerous at highway speeds where loss of engine power means reduced braking and steering assistance. Repair before continued driving; if driving is necessary, avoid high-speed roads.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0374 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition / Engine Timing System
Difficulty
Type
Generic (SAE)
Recommended Tools
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