The P0373: Timing Reference High Resolution Signal A Intermittent/Erratic Pulses code indicates that the engine control module (ECM) is detecting unstable or erratic pulses from the timing reference signal A. This signal is crucial for precise engine timing and synchronization. Erratic pulses can cause performance issues such as misfires, rough idling, or stalling.
P0373 – Quick Overview
Meaning | P0373: Timing Reference High Resolution Signal A Intermittent/Erratic Pulses |
Is it serious? | Yes, this code can lead to engine timing issues, causing misfires, poor performance, or stalling if not addressed, potentially leading to engine damage. |
Possible causes | – Signal instability – Faulty sensor – Wiring issues |
How to diagnose? | – Test timing reference signal A – Inspect sensor and wiring – Replace or repair components if needed |
P0373 Meaning
The P0373: Timing Reference High Resolution Signal A Intermittent/Erratic Pulses code means that the ECM is detecting instability in the timing reference signal A. This signal helps control engine timing and synchronization. If the signal is erratic or intermittent, it can cause the ECM to miscalculate timing, leading to engine misfires, rough idling, or poor performance.
Step-by-step diagnostic guide
Follow these steps to diagnose and resolve the P0373 code by addressing potential causes one by one.
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for additional related codes. These might give more insight into the root cause of the issue. | OBD-II Scanner |
Inspect Timing Reference Sensor A | Visually inspect the sensor for signs of physical damage, wear, or corrosion. Ensure it is securely mounted and connected properly. | Flashlight, Safety Gloves |
Test Timing Reference Signal A | Use a multimeter to test the output from timing reference signal A. Compare the readings with the manufacturer’s specifications to ensure stable signals. | Multimeter, Manufacturer’s Specifications |
Inspect Wiring and Connections | Check the wiring and connectors for signs of damage, loose connections, or corrosion. Ensure there is no intermittent contact. Repair or replace faulty wiring. | Flashlight, Wiring Repair Kit |
Replace the Sensor if Necessary | If the sensor is faulty or providing erratic signals, replace it with a new one to restore stable timing reference signals. | Replacement Timing Sensor, Safety Gloves |
Clear the Code and Test Drive | After completing repairs, clear the P0373 code using an OBD-II scanner. Test drive the vehicle to ensure the issue is resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
Recheck for Codes | After the test drive, re-scan the vehicle to confirm that the P0373 code has not returned. If the code reappears, further diagnosis may be required. | OBD-II Scanner |
This guide will help you identify and resolve the P0373 code, ensuring that timing reference signal A provides stable pulses for accurate engine timing and optimal performance.

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