P065D Reductant System Malfunction Lamp Control Circuit

OBD-II DTC Datasheet

Reductant system malfunction lamp control circuit

What does this mean?

This is a generic Diagnostic Trouble Code (DTC) applicable to many OBD-II vehicles (1996 and newer). This may include, but is not limited to, vehicles from VW, Audi, Chevrolet, Chrysler, Ford, Dodge, GMC, Ram, Volkswagen, etc. Despite the general nature, the exact repair steps may vary depending on the model year, brand, transmission models and configurations. ...

A stored code P065D means that the powertrain control module (PCM) or one of the other associated controllers has detected a mismatch in the reductant system malfunction lamp control circuit.

The reductant system malfunction lamp is an integral part of the dashboard. It is designed to warn the driver about a malfunction in the reductant system. Typically, the PCM receives a signal from one of the sensors in the reductant system. Reductant system sensors allow the PCM to monitor a malfunction of the reductant system. When the reductant system data is calculated by the PCM and a problem is detected, the PCM emits a voltage signal to the reductant system malfunction indicator lamp through the lamp control circuit. When the reductant system malfunction indicator circuit is triggered, the reductant system malfunction lamp should illuminate.

When the key is in the on position (with the engine off), a self-test of all indicator lamps in the instrument panel starts. If a problem is detected while monitoring the reductant system malfunction lamp control circuit, a P065D code will be stored and a malfunction indicator lamp (MIL) may illuminate.

Reducing agent tank DEF:

What is the severity of this DTC?

A P065D should be classified as serious as it could result in an inoperative reductant system, damage to the catalytic converter, and / or driveability problems.

What are some of the symptoms of the code?

Symptoms of a P065D trouble code may include:

Inoperative reductant system
Restore system malfunction lamp does not work
The repair agent system malfunction lamp remains on
Engine control problems
Catalytic Converter Codes

What are some of the common causes for the code?

Reasons for this code may include:

Faulty reductant system malfunction lamp
Open or short circuit in the circuit between the PCM and the instrument panel or other controllers
PCM programming error
Faulty controller or PCM

What are some steps to troubleshoot the P065D?

If other restorer system codes are stored, they should be diagnosed and repaired before attempting to diagnose the P065D.

Consult your vehicle information source for technical service bulletins (TSBs) that reproduce the stored code, vehicle (year, make, model and engine) and symptoms detected. If you find an appropriate TSB, it can provide useful diagnostic information.

A diagnostic scanner and a digital volt / ohmmeter are required to accurately diagnose the P065D code. You will also need a reliable source of vehicle information.

Start by connecting the scanner to the vehicle's diagnostic port and retrieving all stored codes and freeze frame data. You will want to write this information down just in case the code turns out to be intermittent.

After recording all relevant information, clear the codes and test drive the vehicle (if possible) until the code is cleared or the PCM enters ready mode.

If the PCM enters ready mode, the code will be intermittent and even more difficult to diagnose. The condition that led to the persistence of P065D may need to worsen before an accurate diagnosis can be made. On the other hand, if the code cannot be cleared and the symptoms of handling do not appear, the vehicle can be driven normally.

If the P065D reboots immediately, visually inspect the wiring and connectors associated with the system. Belts that have been broken or unplugged should be repaired or replaced as needed.

If the wiring and connectors are OK, use your vehicle information source to obtain related wiring diagrams, connector face views, connector pinout diagrams, and diagnostic block diagrams.

Once you have the correct information, use the DVOM to test the reductant system malfunction lamp control circuit on the appropriate pin on the PCM connector. If the restore agent system malfunction lamp control output is not detected, suspect that the PCM is defective or there is a PCM programming error.

If a restore agent malfunction lamp control output is found at the PCM connector, test the appropriate circuit, as shown, on the instrument cluster restorer malfunction lamp control circuit terminal. If no restorer system malfunction lamp control output is detected, you have an open circuit between the PCM and the restorer system malfunction lamp in the instrument panel. Repair or replace the chain and recheck.

If the malfunction lamp of the reductant system does not come on with the key and engine off, suspect that the malfunction lamp of the reductant system is faulty.
If the P065D code persists and the restorer system malfunction lamp is operating, suspect a defective PCM or PCM programming error

Related DTC discussions

There are currently no related topics in our forums. Post a new topic on the forum now.

Need more help with your P065D code?

If you still need help regarding DTC P065D, post a question in the comments below this article.

NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.