The P0373 diagnostic trouble code (DTC) signifies an issue with the timing reference signal, specifically the high-resolution "A" signal, within your vehicle's engine management system. This signal is crucial for the Powertrain Control Module (PCM) to accurately determine engine position and firing order. When the PCM detects intermittent or erratic pulses from this signal, it sets the P0373 code, indicating a potential problem that needs immediate attention to prevent engine performance issues.
Understanding the root cause of the P0373 code is essential for effective diagnosis and repair. This article will delve into the specifics of the P0373 code, exploring its symptoms, potential causes, diagnostic procedures, and repair solutions.
| Topic | Description | Possible Solutions |
|---|---|---|
| Definition | Timing Reference High Resolution Signal A Intermittent/Erratic Pulses | N/A (This is a definition, not a problem to be solved) |
| Symptoms | Rough idling, stalling, misfires, decreased fuel economy, check engine light | Diagnose the root cause and repair or replace faulty components (sensor, wiring, PCM). |
| Common Causes | Faulty Crankshaft Position Sensor (CKP), Faulty Camshaft Position Sensor (CMP), Wiring or connector issues, Damaged reluctor wheel, PCM failure | Replace or repair faulty sensor, wiring, or connector. Replace damaged reluctor wheel. Reprogram or replace PCM (as a last resort). |
| Diagnostic Tools | OBD-II scanner, Multimeter, Oscilloscope | Use tools to verify sensor output, check wiring continuity, and analyze signal patterns. |
| Testing Procedures | Visual inspection, Sensor testing, Wiring harness testing, PCM testing | Perform visual inspection for obvious damage. Test sensor resistance and voltage. Check wiring for shorts or opens. Test PCM output. |
| Related Codes | P0370, P0371, P0372, P0374, P0335, P0336, P0337, P0338, P0339 | Understanding related codes can help pinpoint the source of the problem. |
| Severity | Moderate to High | Address promptly to avoid potential engine damage. |
| Repair Costs | Varies greatly depending on the cause; Sensor replacement: $100-$500; Wiring repair: $50-$300; PCM replacement: $500-$1500 | Obtain accurate estimates before proceeding with repairs. |
| Impact on Drivability | Significant reduction in performance, potential for no-start condition | Address the issue immediately to restore vehicle drivability. |
Detailed Explanations
Definition: The P0373 code specifically indicates that the PCM has detected an irregular pattern in the high-resolution timing signal "A". This signal is generated by either the crankshaft position sensor (CKP) or the camshaft position sensor (CMP), depending on the vehicle's design. The PCM uses this signal to precisely time fuel injection and ignition events.
Symptoms: The symptoms associated with the P0373 code can vary in severity depending on the extent of the problem. Common symptoms include a rough idling, which can be caused by inconsistent fuel delivery or ignition timing. Stalling can also occur, especially at low speeds or when the engine is under load. Misfires are another common symptom, resulting in a noticeable decrease in engine power and fuel efficiency. You may also experience decreased fuel economy due to inefficient combustion. Finally, the check engine light will illuminate on the dashboard, alerting you to the problem.
Common Causes: Several factors can contribute to the P0373 code. A faulty Crankshaft Position Sensor (CKP) is a common culprit, as this sensor is responsible for providing the PCM with information about the crankshaft's position. Similarly, a faulty Camshaft Position Sensor (CMP) can also trigger the code if it is not providing accurate information about the camshaft's position. Wiring or connector issues, such as damaged, corroded, or loose connections, can disrupt the signal flow between the sensor and the PCM. A damaged reluctor wheel (also known as a tone ring or pulse wheel), which is a toothed wheel attached to the crankshaft or camshaft, can also cause the code if the teeth are damaged or misaligned. In rare cases, a PCM failure can be the root cause, although this is usually diagnosed after ruling out other possibilities.
Diagnostic Tools: To accurately diagnose the P0373 code, several diagnostic tools are essential. An OBD-II scanner is necessary to read the code and access other diagnostic information from the PCM. A multimeter is used to check the sensor's resistance and voltage, as well as to test the continuity of the wiring harness. An oscilloscope is a more advanced tool that can be used to analyze the signal patterns from the sensor and identify any irregularities.
Testing Procedures: The diagnostic process should begin with a visual inspection of the wiring harness and connectors associated with the CKP and CMP sensors. Look for any signs of damage, corrosion, or loose connections. Next, sensor testing should be performed using a multimeter to check the sensor's resistance and voltage output. Wiring harness testing involves checking for shorts, opens, or high resistance in the wiring between the sensor and the PCM. Finally, PCM testing may be necessary if all other components have been ruled out. This usually involves checking the PCM's output signals using an oscilloscope or a specialized PCM testing tool.
Related Codes: Several other DTCs may be related to the P0373 code, providing additional clues about the nature of the problem. These include:
- P0370: Timing Reference High Resolution Signal A
- P0371: Timing Reference High Resolution Signal A Too Many Pulses
- P0372: Timing Reference High Resolution Signal A Too Few Pulses
- P0374: Timing Reference High Resolution Signal A No Pulses
- P0335: Crankshaft Position Sensor A Circuit
- P0336: Crankshaft Position Sensor A Circuit Range/Performance
- P0337: Crankshaft Position Sensor A Circuit Low
- P0338: Crankshaft Position Sensor A Circuit High
- P0339: Crankshaft Position Sensor A Circuit Intermittent
Understanding these related codes can help you narrow down the possible causes and focus your diagnostic efforts.
Severity: The severity of the P0373 code is considered moderate to high. While the vehicle may still be drivable, the underlying problem can lead to significant engine damage if left unaddressed. The misfires and rough idling can put stress on other engine components, and the decreased fuel economy can result in higher operating costs. Therefore, it is crucial to address the issue promptly to avoid further complications.
Repair Costs: The repair costs associated with the P0373 code can vary greatly depending on the underlying cause. A simple sensor replacement can range from $100 to $500, including parts and labor. Wiring repair can cost between $50 and $300, depending on the extent of the damage. In more severe cases, PCM replacement may be necessary, which can cost between $500 and $1500 or more. It is always advisable to obtain accurate estimates from a qualified mechanic before proceeding with any repairs.
Impact on Drivability: The P0373 code can have a significant impact on drivability. The significant reduction in performance due to misfires and rough idling can make the vehicle feel sluggish and unresponsive. In some cases, the vehicle may experience a no-start condition, leaving you stranded. Therefore, it is important to address the issue immediately to restore vehicle drivability and prevent further damage.
Frequently Asked Questions
What does the P0373 code mean? It indicates an intermittent or erratic signal from the timing reference high-resolution "A" circuit, usually related to the crankshaft or camshaft position sensor.
Can I drive my car with a P0373 code? While you might be able to drive, it's not recommended as it can lead to further engine damage. Address it promptly.
What is the most common cause of the P0373 code? A faulty crankshaft or camshaft position sensor is the most frequent culprit, followed by wiring issues.
How do I fix the P0373 code? Diagnose the root cause using an OBD-II scanner, multimeter, and oscilloscope, then repair or replace the faulty component.
Is the P0373 code expensive to fix? The cost varies depending on the cause, but sensor replacement is usually less expensive than PCM replacement.
Conclusion
The P0373 code signals a problem with the timing reference signal, which is vital for engine operation. Addressing this issue promptly by diagnosing and repairing the underlying cause is crucial to prevent engine damage and restore optimal performance.