You probably know about DTCs or Diagnostic Trouble Codes – messages from your jeep’s computer to let you know there’s a problem. The Jeep Grand Cherokee, like any other vehicle, can sometimes experience them, one of which is the P0320.
This code appears when the ECM or Engine Control Module detects a problem with the ignition/distributor engine speed circuit. Read on to learn its meaning, causes, and how to troubleshoot it.
What Does P0320 Jeep Grand Cherokee Code Mean?
The OBD-II code P0320 in Jeep Grand Cherokee is an indication of a malfunction in the ignition/distributor engine speed circuit. Specifically, it points to a problem with the crank position sensor or the sensor’s circuit.
Crank position sensors send signals to the engine control module (ECM) regarding the crankshaft’s position, which the ECM uses to control ignition timing and fuel injection.
When the ECM can’t get the right signals from the crank position sensor, it sets P0320 and illuminates the check engine light. This can cause the engine to vibrate, misfire, lose power, or stall.
Here’s the breakdown of the P0320 code.
- P = Powertrain, the components system that propels your vehicle.
- 0 = A generic, or “global,” code; applies to all OBD-II-equipped vehicles.
- 3 = Indicates a manufacturer-specific code for ignition system or misfire.
- 20 = Specific fault index, denoting a problem with the crank position sensor. Here, it indicates a crank position sensor circuit failure.
P0320 Code: What Causes Ignition/Distributor Engine Speed Circuit Failure on Jeep Grand Cherokee?
Knowing the potential causes of P0320 is key for identifying and diagnosing your Grand Cherokee’s ignition/distributor engine speed circuit issue. To get the right fix, it’s important to be aware of all possible causes.
A faulty Crank/Cam sensor is the main cause of the P0320 code, which can happen due to the following occurrences.
- A poor electrical connection in the Crankshaft Position Sensor (CKP) circuit
- An open or shorted Crankshaft Position Sensor (CKP) harness
- A faulty Powertrain Control Module (PCM)
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How to Troubleshoot & Fix P0320 Jeep Grand Cherokee Code?
As the Crank/Cam sensor is usually the cause of this code, your first reaction might be to replace it right away. However, before replacing any parts, you should always follow the step-by-step diagnostic process and identify the root cause of the problem.
Here’s how you should proceed.
1. Look for Other Similar Codes and TSBs
To help figure out the cause of the P0320 code in your Grand Cherokee, check for other codes related to the crank or cam sensors. For instance, if you see a code like P0336, it suggests an issue with the performance or range of the crank sensor.
Jeep uses Technical Service Bulletins to keep repair professionals informed about common problems.
You can find them on the NHTSA website and search by your Grand Cherokee’s VIN number. These bulletins are updated yearly, so you’ll have the latest information.
2. Inspect the Ignition Wiring
Next, you need to check the ignition system’s wiring harness for cracks, burns, loose connections, and other damages.
Start with the crank and camshaft sensors wiring and follow it to the PCM. The issue with the engine speed sensor signal should be before the wiring enters the PCM. Remember, the P0320 code indicates a problem with your Grand Cherokee’s engine speed sensor signal.
If the wiring looks good, inspect the harness going to the coil packs from the PCM and ensure it has a strong ground connection. Sometimes, if the harness can’t report back to the PCM that the coil packs fired correctly, it can cause the P0320 code.
Check all the grounding terminals in the engine bay and ensure they’re clean and free of corrosion.
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3. Check the Hall Effect Sensor
If the P0320 code holds on, you’ll need to inspect the hall effect sensor inside the distributor before checking the crank position sensor or cam sensor. This is because bad hall effect sensor readings will incorrectly report the engine speed.
The hall effect sensor is a three-wire system connected to the distributor and reports the engine speed to the PCM.
To check this sensor, you can do the following:
- Disconnect the harness going to the Camshaft and the Crankshaft Position Sensors
- Test the 5V power supply circuit going to each sensor to ensure it is being powered up
- Test each signal circuit going to each sensor to ensure it has a signal circuit
- Check for good ground at each sensor
- Wiggle the wiring harness going to each sensor to see if there is an intermittent connection.
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4. Test Your Engine’s Speed Sensor
Next, you will need to test your jeep’s engine speed sensor, the focal point of the P0320 code. In different Grand Cherokee years and engine combinations, it could be the crankshaft or camshaft sensor, coil pick-up sensor (for distributor only), or coil sensor wiring.
To learn how to test them, you can watch the following video.
5. Check the PCM
Lastly, If the wiring connected to the engine speed sensor is in good order and the sensor is functioning correctly, your Jeep might have a malfunctioning Powertrain Control Module.
Although it’s rarely to blame for a P0320 code, you can’t rule it out since it processes the engine speed sensor signal.
You can either replace the PCM or have it flashed and calibrated by a professional to try and reset any error messages stored inside.
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Frequently Asked Questions
If you’ve been troubleshooting the P0320 code in your Jeep Grand Cherokee and still have other questions, here are some commonly asked questions and answers to help you out.
What are the symptoms of the P0320 code in Jeep Grand Cherokee?
The signs of a P0320 code in a Grand Cherokee may differ based on the cause. Your vehicle may not start, die without warning, or lose power. Also, it may start fine when warm but not when cold.
Can you drive a Jeep Grand Cherokee with a P0320 code?
Driving with a P0320 code isn’t recommended. The P0320 code usually results from a bad crankshaft position sensor, which can cause the engine to misfire and stall. This can be dangerous and can lead to further damage to the vehicle.
How much does it cost to fix Jeep Grand Cherokee P0320 code?
Repairing the P0320 code on a Jeep Grand Cherokee is relatively inexpensive. The cost varies based on the components and the work done besides your location. The crank position sensor is usually the most expensive, costing around $100-$150.
Fixing a P0320 code on your Jeep Grand Cherokee requires patience and attention to detail. But following the above diagnosis steps closely will help you pinpoint and fix the problem quickly.
However, if the issue persists after completing all these steps, seeking professional help is your only way out.
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