What Does P0373 Mean?
The ECM has detected an intermittent or erratic signal from the primary (A) timing reference high-resolution sensor, which is typically the crankshaft position sensor. This sensor provides precise crankshaft position data used for fuel injection and ignition timing calculations. The driver may experience rough running, misfires, stalling, or a no-start condition depending on the severity of the signal disruption.
Safety Warning
An intermittent CKP signal can cause sudden engine stalling at any speed, including highway driving. This creates a serious safety hazard as power steering and brake assist are lost. The vehicle should be diagnosed and repaired promptly; avoid highway driving until resolved.
Common Causes
35%
Damaged or corroded crankshaft position sensor wiring or connector causing intermittent contact
30%
Failing crankshaft position sensor with intermittent output
20%
Damaged or contaminated reluctor wheel (tone ring) with debris or missing teeth
10%
Excessive crankshaft endplay or sensor air gap out of specification
5%
ECM ground or power supply issue causing erratic signal interpretation
Diagnostic Steps
1
Monitor CKP sensor live data with the engine running; watch for signal dropouts, erratic RPM readings, or sudden jumps in the crankshaft position PID.
2
Inspect the CKP sensor connector and wiring harness for corrosion, chafing, oil contamination, or loose pins. Wiggle-test the connector while monitoring live data for signal disruption.
3
Using an oscilloscope, capture the CKP sensor waveform at idle and 2500 RPM. Verify a clean, consistent AC sine wave (for magnetic sensors, typically 0.5-2V AC at idle) or clean digital square wave (for Hall-effect sensors, typically 0-5V).
4
Measure the CKP sensor air gap with a feeler gauge; typical specification is 0.5-1.5mm. Inspect the reluctor wheel through the sensor bore for damaged, missing, or contaminated teeth.
5
Check CKP sensor resistance (magnetic type: typically 500-1500 ohms) and compare to manufacturer specification. Also verify no shorts to ground or power on signal wires.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The ECM has detected an intermittent or erratic signal from the primary (A) timing reference high-resolution sensor, which is typically the crankshaft position sensor. This sensor provides precise crankshaft position data used for fuel injection and ignition timing calculations. The driver may exper...
The most common cause of P0373 (Timing Reference High Resolution Signal A Intermittent/Erratic Pulses) is: Damaged or corroded crankshaft position sensor wiring or connector causing intermittent contact
Typical repair costs for P0373 range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
An intermittent CKP signal can cause sudden engine stalling at any speed, including highway driving. This creates a serious safety hazard as power steering and brake assist are lost. The vehicle should be diagnosed and repaired promptly; avoid highway driving until resolved.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0373 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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