P0602 Diagnostic Trouble Code: Control Module Programming Error

Fault code P0602 is called “Control Module Programming 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 P0602

OBD-II code P0602 is defined as “control module programming error”. Set when a software error is detected in the powertrain control module (PCM).

P0602 Diagnostic Trouble Code: Control Module Programming Error

If you look at the PCM unit, you see a simple metal box. But it’s what’s inside that’s important to the efficient operation of the engine. The information that is vital to engine control is programmed at the factory. Using electronically erasable programmable permanent memory (EEPROM).

The engine and transmission control settings for a particular vehicle are programmed into the EEPROM for each vehicle leaving the factory. The EEPROM not only helps manage engine efficiency and performance. But it also serves to recognize and interact with other on-board vehicle control modules.

If the PCM detects a mismatch with the EEPROM, or if it is unable to recognize the EEPROM program. Then code P0602 will be stored and the Malfunction Indicator Light (MIL) may illuminate. Depending on the severity of the fault, it may take several ignition cycles (with the fault) for the indicator lamp to turn on.

Essentially, error P0602 means there is a software problem in the powertrain control module (PCM).

Symptoms of vehicle malfunctions

The main signal that an error P0602 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. The “Check engine” control lamp on the control panel will light up (the code will be recorded in the memory as a fault).
  2. Floating revolutions, as well as attempts to stall at idle.
  3. Multiple handling problems.
  4. Sharp or unstable shifting of automatic transmission.
  5. Reduced engine power.
  6. Increased fuel consumption.
  7. Problems with a particular system, indicating a possible loss of communication in that area.

Code P0602 indicates an EEPROM programming error. Depending on what the failure affects, the error may be severe or moderate.

Factors that can cause this error code

The error code P0602 can mean that one or more of the following problems have occurred:

  • Powertrain Control Module (PCM) programming error.
  • If the engine control module has been replaced, it may need to be programmed.
  • Bad power supply relay of ECM / PCM.
  • Open or short circuit in wiring harness.
  • Loose or damaged connectors.
  • Poor grounding is a common cause.
  • Blown engine-ECU fuse.
  • CAN bus may be faulty and have a short to ground or wire breakage.
  • Sometimes the cause is a faulty PCM module.

How to fix or reset OBD-2 code P0602

Some suggested steps for troubleshooting and fix the error code P0602:

  1. Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0602 appeared.
  2. Clear the error codes from the computer memory and test-drive the vehicle to find out if the malfunction appears again.
  3. If the error code appears again, visually inspect the electrical wires and powertrain control module (PCM) connector.
  4. Measure battery voltage and compare it to the manufacturer’s specification.
  5. Check continuity of powertrain control module (PCM) power and ground circuits with multimeter.
  6. Try reprogramming the control module.
  7. Evaluate Powertrain Control Module (PCM) operation following vehicle manufacturer’s procedure.
  8. Clear the error code from the computer memory again, and test drive the vehicle to see if the problem is resolved.

Diagnose and repair of problems

To correct code P0602, 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 P0602 code remains despite following the steps above. One option may be to replace the entire electrical harness. However, this does not guarantee that the problem will be solved because 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.

Checking and reprogramming

If the PCM has recently been replaced, there is a good chance that it has been improperly programmed or not programmed at all. In addition, you cannot use a controller from another vehicle. Unless it has been reprogrammed specifically for the vehicle in question.

Aftermarket (high performance) firmware may not be recognized by other controllers, resulting in a stored P0602.

Improperly programmed or replaced controllers may be reprogrammed by the factory scan tool. If you can’t access such a scanner, most dealerships offer PCM programming for a nominal fee.

Some aftermarket PCM manufacturers offer preprogrammed controllers for certain models. Contact your auto parts supplier and get the vehicle identification number, mileage, and other pertinent data.

On which vehicles does this problem occur most frequently

Fault code P0602 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Chevrolet (Silverado)
  • Citroen
  • Dodge (RAM)
  • Ford (Focus, Mustang, Ranger)
  • GMC
  • Honda
  • Hyundai
  • Isuzu
  • Kia (Sportage)
  • Mazda
  • Opel (Astra, Corsa, Meriva)
  • Peugeot (308)
  • Volkswagen
  • Volvo (S40, V40, XC90)

Fault code P0602 can sometimes be found with other errors. The most common are the following: P0100, P0136, P0142, P0171, P0174, P0216, P0601, P0603, P0604, P0605, P0700, P1689, U0101.


Rate article
Share to friends
AutoNevod | Technical description of OBD-2 car faults and their solution
Add a comment