Fault code P0606 is called “PCM Processor Fault” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0606
OBD-II fault code P0606 is a generic code defined as ” Processor failure of the transmission control module (PCM)”. It is set when a processor error is detected in the powertrain control module (PCM).
The PCM serves as the primary controller, whose main task is to control the operation of the engine and transmission. In addition, it controls various functions of other electronic systems (other controllers). The data exchange between these controllers takes place by means of a large and complex network of wires, also called Controller Area Network (CAN).
When the ignition key is turned to the “on” position, without starting the engine, the PCM begins a series of self-tests to determine if it is operating properly.
If the PCM detects a power supply fault, a system ground fault, or an internal processor error. Then code P0606 will be stored and the Malfunction Indicator Light (MIL) may illuminate.
Depending on the perceived severity of the fault, it may take several fault ignition cycles for the MIL to come on.
Symptoms of vehicle malfunctions
The main signal that an error P0606 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be written in the memory as a malfunction).
- Multiple problems with engine controllability.
- Sharp or unstable shifting of automatic transmission.
- Floating revolutions, as well as attempts to stall at idle.
- Decrease of engine power when accelerating the vehicle.
- Possible ignition skips in the engine cylinders.
- Increased fuel consumption.
- Other problems may be displayed, as well as fault codes.
The diagnosis code P0606 is considered serious, as it may cause problems with the engine and vehicle controllability. The engine may suddenly stall or run erratically. For this reason, this error should be corrected as soon as possible.
Factors that can cause this error code
The error code P0606 can mean that one or more of the following problems have occurred:
- Faulty ECM / PCM module.
- ECM / PCM power relay has failed.
- Damaged, corroded wiring or connectors.
- Damaged PCM ground circuit or faulty data output device.
- Open or short circuit in CAN circuit.
- Control box fuse blown.
- Low battery voltage.
How to fix or reset OBD-2 code P0606
Some suggested steps for troubleshooting and fix the error code P0606:
- Inspect the wiring for damage, abrasions, breaks, and shorts. If the wiring is damaged, repair or replace it.
- Disconnect and test each CAN bus pin with a special diagnostic scanner.
- Inspect and check the fuse and fusible link.
- Check the wiring diagram of the relay and fuse system.
- If the problem persists, the PCM may need to be replaced and reprogrammed.
Diagnose and repair of problems
Diagnosing a P0606 code can be a daunting task even for the most experienced and well-equipped technician. However, there are a few preliminary tests that can be performed before calling for service to replace the PCM.
Start with a visual inspection of all visible wires and harnesses associated with the vehicle’s controllers. Using a multimeter, check the ground to the engine and bodywork to make sure they are OK.
Battery connection
To rule out all possibilities of error P0606, you should visually inspect the wiring, check the voltage on the battery. You should also check the battery terminals and cables for loose connections.
Make sure that the voltage in the system corresponds to the value specified in the manual. The charging system is fully operational and the battery is in good condition, begin the diagnostic procedure.
Further verification
Locate the ECM / PCM and inspect it for damage caused by water, heat or collision. If the PCM is damaged, especially by water, it is likely out of service and needs to be replaced.
Next, check the fuses and relays on the ECM / PCM power supply. Inspect and replace the blown fuses as well as the relay connector.
If the ECM / PCM power supply code is also present along with error P0606, correct it first before troubleshooting this fault.
After the tests are done, recheck the error, if the error is still present, the ECM / PCM module is most likely defective. Replacing the ECM / PCM or any other controller usually requires reprogramming for the specific vehicle.
On which vehicles does this problem occur most frequently
Fault code P0606 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Audi (A4)
- Chevrolet (Captiva, Cruze, Epica, TrailBlazer, Volt)
- Citroen (C3, C4, C5, Picasso) (Avenger, Caliber, Caravan, Challenger, Charger, Dakota, Dart, Durango, Grand Caravan, Intrepid, Journey, Magnum, Neon, Nitro, RAM, Stratus)
- Fiat (Stilo)
- Ford (Connect, Escape, Explorer, F-150, Fiesta, Focus, Transit)
- GMC (Envoy)
- Honda (Accord, CR-V, Civic)
- Hyundai (Tucson)
- Infiniti
- Kia (Rio)
- Land Rover (Freelander)
- Lexus (GS300, GX470)
- Mazda (3, 6)
- Mercedes-Benz
- Mitsubishi (ASX, Colt, Outlander)
- Nissan (Micra, X-Trail)
- Opel (Antara, Astra, Vectra, Vivaro, Zafira)
- Peugeot (207, 3008, 307, 406, 407, 607, Boxer)
- Renault (Fluence, Mascott, Megane)
- Saab (9-3)
- Saturn (VUE)
- Scion (tC)
- Skoda (Fabia, Octavia)
- Subaru
- Toyota (Corolla, Land Cruiser, Prado, Prius)
- Volkswagen (Crafter, Passat, Polo, Tiguan)
- GAZelle (Business)
- LADA (Granta, Kalina, Niva, Priora)
- VAZ
Fault code P0606 can sometimes be found with other errors. The most common are the following: P0171, P0174, P0345, P0600, P0601, P0602, P0603, P0604, P0605, P0607, P0608, P0609, P0610, P0638, P0642, P1319, P2106, C1201.
