Fault code P0601 is called “Internal Control Module Memory Check Sum Error” 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 P0601
OBD-II code P0601 is defined as “internal control module memory checksum error”. It is set when the transmission control module (PCM) detects a communication failure between itself and the auxiliary control modules.
When a communication failure occurs in any area of the CAN system, the code will be stored and the warning light will come on. Depending on the vehicle, it may take several drive cycles before the code is stored and the warning light comes on.
The CAN controller network includes control modules for all vehicle systems. The actual number of control modules that make up the CAN system varies by manufacturer and model.
The CAN system controls every aspect of the vehicle’s operation. The microprocessors and controllers in the vehicle are constantly exchanging messages and signals between themselves and the sensors they control.
This is accomplished by intricately interconnecting wiring harnesses to create a “distribution pipeline.” Which conveys input and signal voltages to various sensors, components, systems and other controllers. Signals go both to and from the PCM.
Essentially, error P0601 means there is an internal fault in the powertrain control module (PCM).
Symptoms of vehicle malfunctions
The main signal that an error P0601 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be stored in the memory as a malfunction).
- The ABS and traction control system light may illuminate.
- Transmission light illuminated (transmission may not shift properly).
- Floating revolutions, and attempts to stall at idle.
- Reduced engine power.
- Increased fuel consumption.
- Problems with a particular system, indicating a possible loss of communication in that area.
- There may be no symptoms other than a stored fault code.
Code P0601 indicates an internal failure in the powertrain control module (PCM). Depending on what the failure affects, the error may be severe or moderate.
Factors that can cause this error code
The error code P0601 can mean that one or more of the following problems have occurred:
- Powertrain Control Module (PCM) has failed.
- Low battery voltage.
- Open or short circuit in the wiring harness.
- Loose or damaged connectors.
- Poor grounding is a common cause.
- CAN bus may be faulty and have a short to ground or wire breakage.
How to fix or reset OBD-2 code P0601
Some suggested steps for troubleshooting and fix the error code P0601:
- Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0601 appeared.
- Clear the error codes from the computer memory and test-drive the vehicle to see if the fault appears again.
- If the error code appears again, visually inspect the electrical wiring and the Powertrain Control Module (PCM) connector.
- Measure battery voltage and compare it to the manufacturer’s specification.
- Check continuity of powertrain control module (PCM) power and ground circuits with multimeter.
- Evaluate Powertrain Control Module (PCM) operation following vehicle manufacturer’s procedure.
- Clear the error code from the computer memory again, and test drive the vehicle to determine if the problem has been resolved.
Diagnose and repair of problems
To correct code P0601, the most common solution is to replace and reprogram the PCM. Although, faulty wiring should also be considered as a cause of this error.
Perform a thorough visual inspection of all points where the wiring rests on the body. These points represent ground connections. You will often find loose connections or even ground straps that hang down after unrelated repairs have been made.
If bad ground connections have been found and repaired, remove all codes and re-scan the system to see if any codes return. In some cases it may be necessary to re-integrate or even reprogram some controllers after a communication failure.
If all ground connections are secure, perform a thorough visual inspection of all wiring on the vehicle. Note that this inspection may require the removal of the dashboard, seats, carpets, and even trim panels to gain access to all wiring harnesses.
If no wiring damage is found, but the P0601 code remains despite following the steps above. One option may be to replace the entire electrical harness. However, this is not guaranteed to solve the problem as the problem may be related to the controller.
Typical problems with controllers include faulty drivers, memory failure, or other components for any number of reasons. For this reason, replacing the entire harness is not recommended. Until exhaustive diagnostic tests have been performed on all controllers, including the PCM.
On which vehicles does this problem occur most frequently
Fault code P0601 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
- BMW (E39, E46)
- Chevrolet (Cruze, Lacetti, TrailBlazer)
- Chrysler (PT Cruiser, Town and Country, Voyager)
- Daewoo (Matiz)
- Dodge (Caravan, RAM, Stratus)
- Fiat (Ducato)
- Ford
- GMC
- Jeep
- Kia
- Mazda
- Opel (Astra, Mokka, Zafira)
- Renault (Kaptur)
- Saab
- Volkswagen (Passat)
- Volvo
- GAZelle (Chrysler)
- LADA (Kalina, Priora)
- VAZ (2107, 2110, 2112, 2114, 2115)
Fault code P0601 can sometimes be found with other errors. The most common are the following: P0014, P0128, P0300, P0449, P0600, P0602, P0603, P0604, P0605, P0606, P0607, P0608, P0609, P0610, P0700, P1345.
