Dodge Caravan PCM Problems – How to Diagnose and Solve Them?

The Dodge Caravan and its long-wheelbase version, the Grand Caravan, certainly had a long run in the market. It went on in the span of more than three decades from the introduction of its 1984-year model unit up to its eventual discontinuation after the 2020 model year. Whether it was used as a people or cargo mover, it surely served its purpose for plenty of owners.

PCM problems highlights

• Module's importance:Extremely high
• Prone to failure:Yes
• Reasons for failure:Water, damage, ECM problems, TCM problems
• Ways to reset:Disconnecting, scanner tool diagnostics
• Sphere of control:Powertrain (engine, transmission, AWD systems)
• Symptoms of failing:Powertrain anomalies, powertrain codes
• Price to repair:$180 - $300
• Price to replace:$750 - $1,650

Symptoms of a Bad PCM in the Dodge Caravan

If your Dodge Caravan's PCM is failing, you may notice one or more of the following symptoms:

• The engine stalls or hesitates during acceleration. This can be caused by a loss of communication between the PCM and the engine, which can result in the engine misfiring.
• The engine runs rough or idles poorly. This is often due to a loss of power from the PCM, which can cause the engine to run lean or rich.
• The check engine light is illuminated on the dash. This can be caused by a variety of issues, including a faulty sensor or a problem with the PCM itself.
• The vehicle refuses to start. This is usually caused by a problem with the PCM's ability to provide power to the starter motor.
• The transmission shifts erratically or not at all. This can be caused by an inaccurate or lack of information flow between the PCM and the transmission, which can cause the transmission to shift improperly.

If you notice any of these symptoms, it is important to have your Caravan's PCM checked by a qualified mechanic as soon as possible. Ignoring these symptoms can lead to further damage to your vehicle and may even render it undrivable.

Isolating the Problem

Before ruling out the issue as a problem with the PCM hardware or software itself, it is important to take several efforts to eliminate the other factors that may be causing a fault code or warning to come out in your dashboard. That's because even if those other problems are not addressed, the fault codes or errors in your PCM will remain even if you update its software or replace its hardware.

For example, if your engine is stalling, showing signs of hesitation, or losing performance, you might have a dirty or clogged air filter. If your air filter is dirty, it can restrict the flow of air to your engine, causing its bad performance.

Another common culprit is a faulty fuel system, which can be due to a bad fuel quality or a problem with its components like the fuel pump and injectors. Of course, there are plenty of other things that may trigger the various error codes in your PCM, so a thorough check is definitely needed before anything else.

Diagnostics Through Visual Inspection

There are different ways to tell if there is a problem with your PCM. Aside from the recurring error codes in your dashboard that do not correspond to a real issue on the part that they are warning you about, you can diagnose a faulty PCM by looking at it.

Here are some visual cues to help you spot a problem:

• Check for physical damage like cracks on the hardware. If the PCM is damaged, it may not function properly. The PCM is located under the hood on the driver's side. It should be on the frontmost area of your engine bay just beside the battery.
• Look for signs of corrosion. Corrosion can cause electrical problems that may prevent the PCM from working correctly.
• Inspect all the connections. Make sure that all the connections are secure to guarantee the proper flow of current in your van's electronic components, including the PCM.
• Use your vehicle manual to locate the different sensors of your van. Check them out for possible wear or dirt build-up.

Diagnostics Using a Multimeter

One of the common causes of PCM problems in the Dodge Caravan is a worn or drained battery. Aside from the flickering lights, malfunctioning electronics, and performance issues in your vehicle, a way to tell that you have a bad battery is via a multimeter. This is a relatively simple process, but it's important to follow the steps carefully in order to get accurate results.

• Start by setting your multimeter to the "DC volts" setting.
• Next, attach the positive lead of the multimeter to the positive terminal of the battery, and the negative lead to the negative terminal.
• If the voltage reading is 12.6 volts or higher, this indicates that the battery is in good condition. Anything below 12.6 volts indicates a bad battery.
• Finally, to double-check the results, you can also test the voltage while the engine is running. This should give you a reading of around 13.8 volts.

If you followed these steps and your multimeter indicates a bad battery, it's time to replace it. However, if everything checks out well, proceed with the wirings.

• Again, make sure that the multimeter is set to the correct settings. You'll want to set it to ohms or continuity mode.
• Once it's set, touch the probes to the wires that you think might be causing the problem.
• If the multimeter shows high resistance, that means there is a break in the wire. If there is no continuity, that means the wire is completely severed. either way, you'll need to replace the wire.

If the multimeter doesn't show anything, that means the wire is still intact. You can now proceed with the sensors associated with the fault displayed on your dash.

• Set your multimeter for resistance measurements, so you'll want to use the ohmmeter setting here.
• Locate the sensor you wish to test and disconnect it from the wiring harness.
• Once the sensor is disconnected, place one lead of the multimeter on the sensor's signal wire terminal and the other lead on the sensor's ground wire terminal.
• If the multimeter reads infinite resistance, then the sensor is most likely faulty and needs to be replaced.

When you're done with the sensors and they appear to be working okay, it's time for you to check the PCM. To confirm a problem with the device itself, all you have to do is follow the steps below:

• Begin by disconnecting the negative battery terminal. This will prevent any potential shocks while you're working.
• Locate the PCM. It should near the battery on the driver's side of the vehicle.
• Once you've found it, remove the cover and expose the circuitry inside.
• Using your multimeter, set it to the "resistance" or "ohms" setting.
• Touch the multimeter leads to the two PCM terminals. If the reading is "infinite" or very high, it indicates a problem with the PCM hardware. In this case, a replacement is surely needed.

Diagnostics Via a Scanner

If you're having trouble with your Dodge Caravan's PCM, the easiest way to diagnose the cause of the problem is via a scanner. Depending on the year model of your van, you will have to use either an OBD or OBDII scanner for it. In the US, an OBDII port has become a mandatory fit for all vehicles produced in 1996.

Here are steps to diagnose the problem using a scanner:

• Connect the OBD or OBDII scanner to the Caravan's diagnostic port.
• Turn on the scanner and select the "PCM" option.
• Follow the prompts to run a scan of the Caravan's PCM.
• Review the results of the scan and look for any codes that indicate a problem.
• If you find a code, research it to see what it means and how to fix it.
• Fix the problem and clear the code from the scanner.

Following these steps should help you get your Caravan's PCM working again. If you're still having trouble or the problem has recurred, you may need to take your Caravan to a mechanic for further diagnosis and repairs.

Solutions

If you suspect that your PCM is faulty, it's important to have it replaced as soon as possible. A faulty PCM can cause all sorts of problems with your vehicle, so it's best to nip the issue in the bud before it becomes a bigger problem.

If the issue can only be traced to bad connections simply fixing them will do the job. Now, if it's the battery or sensors causing your PCM troubles, just have them changed with new ones.

No matter where the issue is coming from, be sure to get the services of a qualified mechanic to help you better zero in on the source of the problem and make the right calls on the needed repairs.

The PCM is a very delicate part of your Dodge Caravan, so an inaccurate diagnosis that will yield wrong solutions will only bring in more problems that will require more expensive repairs down the road.