You’re driving along, feeling in control, when suddenly your speedometer starts acting up. The needle’s jumping around, and you’re left wondering what’s going on. That’s when the check engine light comes on, and you’re faced with the P1720 code. This malfunction in your vehicle’s speed meter circuit can lead to some serious issues, from transmission shifting problems to faulty ABS warnings. But what’s causing it? Is it a faulty speed sensor, a wiring problem, or something more complex? You’ll need to dig deeper to find out – and fix it fast to avoid further damage.
Key Takeaways
- The P1720 code is triggered by a malfunction in the vehicle speed meter circuit, affecting engine operation, transmission shifting, and cruise control.
- Common causes of the malfunction include speed sensor issues, wiring problems, and corrosion or debris in the speed sensor connections.
- Symptoms of the P1720 code include inaccurate speedometer readings, malfunctioning ABS or traction control warning lights, and shifting problems.
- Diagnosing the issue involves inspecting the speed sensor, wiring, and connectors for damage or corrosion, and testing the speed sensor using a multimeter.
- Repairing the speed meter circuit may require replacing the speed sensor, cleaning or replacing connections, and resetting the Engine Control Module.
Code P1720 Description and Purpose
When your vehicle’s onboard computer, the Engine Control Module (ECM), detects a malfunction in the vehicle speed meter circuit, it triggers the P1720 code.
This code indicates a problem with the circuit that measures your vehicle’s speed and transmits it to the ECM. The ECM relies on accurate speed data for proper engine operation, transmission shifting, and cruise control.
Inaccurate speed readings can lead to drivability issues, affecting your vehicle’s performance. The circuit’s complexity demands precision, making speedometer accuracy vital.
The P1720 code signals a malfunction that needs attention to guarantee your vehicle operates smoothly and efficiently.
Common Causes of the Malfunction
Since the P1720 code is triggered by a malfunction in the vehicle speed meter circuit, it’s essential to identify the root cause of the problem.
You’ll need to investigate the common causes of the malfunction to get your vehicle back on track. Speed sensor issues are a common culprit, as a faulty sensor can send inaccurate speed data to the engine control module.
Wiring problems, such as damaged or corroded connections, can also disrupt the circuit and trigger the P1720 code. Additionally, malfunctioning engine control modules, corrosion or debris in the speed sensor connections, and vehicle speedometer gauge malfunctions can all contribute to the problem.
Identifying P1720 Code Symptoms
Now that you’ve identified the potential causes of the P1720 code, it’s time to recognize the symptoms that’ll help you pinpoint the problem.
Inaccurate speedometer readings are a common symptom, which can lead to issues with vehicle performance.
You might notice your speedometer gauge is malfunctioning, displaying incorrect speeds or fluctuating wildly.
Other symptoms include illuminated ABS or traction control warning lights, shifting problems, engine stalling or hesitation, and loss of cruise control functionality.
These symptoms can significantly impact your driving experience and overall vehicle performance.
Diagnosing the Vehicle Speed Meter
To diagnose the vehicle speed meter, you’ll need to inspect the speed sensor, wiring, and connectors to identify the source of the malfunction. This involves a thorough vehicle inspection, focusing on the speed sensor location, which is usually found on the transmission or differential.
| Inspection Point | What to Look For |
|---|---|
| Speed sensor | Corrosion, debris, or damage |
| Wiring | Damaged, frayed, or pinched wires |
| Connectors | Corrosion, loose connections, or damage |
| Speed sensor connections | Corrosion, loose connections, or damage |
| Vehicle speedometer gauge | Malfunctioning or inaccurate readings |
Repairing the Speed Meter Circuit
Faulty speed meter circuits demand immediate attention to prevent exacerbating drivability issues and potential safety hazards.
When repairing the speed meter circuit, you’ll need to perform a thorough circuit overhaul. Start by inspecting the vehicle speed sensor and its connections for signs of corrosion or debris. Clean or replace the connections as needed.
Next, test the speed sensor using a multimeter to verify it’s operating within the specified range. If it’s faulty, replace it with a new one and perform sensor calibration to guarantee accurate speed readings.
Additionally, inspect the wiring and connectors for damage and repair or replace them as necessary. By following these steps, you’ll be able to restore accurate speed data to the engine control module and resolve the P1720 code.
Resetting the Engine Control Module
Accuracy is key in regards to engine performance, and a properly reset engine control module (ECM) is crucial in guaranteeing the P1720 code is cleared and the vehicle operates smoothly. After repairing the speed meter circuit, you’ll need to reset the ECM to reinitialize the engine calibration. This process guarantees the ECM receives accurate speed data, allowing the vehicle to operate efficiently.
| Step | Action |
|---|---|
| 1 | Disconnect the battery to erase the ECM’s memory |
| 2 | Wait for 30 minutes to allow the capacitors to discharge |
| 3 | Reconnect the battery and start the engine |
| 4 | Allow the engine to idle for 10 minutes to relearn the engine calibration |
| 5 | Test drive the vehicle to guarantee accurate speedometer readings and proper system function
P1720 Code Repair Cost and Info
When you’re faced with a P1720 code, one of the most significant concerns is the cost of repair.
The cost factors include the extent of the issue, parts cost, and labor costs. Typical repair costs range from $150 to $500.
It’s essential to consult a qualified mechanic for an accurate quote for your specific vehicle. Diagnostic tools, such as a multimeter, are necessary to test the vehicle speed sensor and identify the root cause of the issue.
A thorough diagnosis will help determine the necessary repairs and provide a more accurate estimate of the repair cost. Be sure to get access to factory service manuals for more information on fixing the P1720 code.
Importance and Detection of the Malfunction
The malfunction detected by the P1720 code is critical to address promptly, as it affects the overall performance and drivability of your vehicle.
As the engine control module relies on accurate speed data for proper engine operation, any inaccuracies can lead to issues with transmission shifting and cruise control.
To detect the malfunction, your vehicle’s onboard diagnostics (OBD II) system integrates with the speed sensor calibration to monitor the vehicle speed meter circuit.
If the system detects a difference between two vehicle speed sensor signals out of the specified range, it will trigger the P1720 code.
It’s essential to address this issue promptly to prevent further damage and guarantee your vehicle operates safely and efficiently.
Conclusion
As you cruise down the highway, feeling like you’re in control, your vehicle’s speedometer might be lying to you. You’re moving at a steady 60, or so you think. In reality, your car’s computer is getting faulty readings, causing your transmission to shift erratically and your cruise control to malfunction. It’s a recipe for disaster, all because of a faulty speed sensor or wiring issue. Don’t wait until it’s too late – get your P1720 code checked and repaired before you’re left stranded on the side of the road.
