Technical Description of OBD-II Trouble Code
The control circuit for Cooling Fan 3 is experiencing high voltage
What does that signify?
This is a generic diagnostic trouble code (DTC) related to the powertrain and is applicable to most vehicles manufactured from 1996 onwards. The specific steps for repair may vary depending on the make and model of the vehicle.
The electric motors used to cool the engine’s radiator are responsible for operating the fans. The powertrain control module (PCM) turns these motors on and off based on readings from the engine coolant temperature sensor (ECT). In other words, when the ECT reaches a certain temperature, the PCM activates the fans. When the ECT cools down to a predetermined temperature, the PCM turns the fans off.
The PCM controls the cooling fans by sending a ground signal to the cooling fan relay. When the fans are not commanded on (not grounded), the voltage on the signal circuit is high, approximately equal to the battery voltage. Conversely, when the fans are commanded on (grounded), the voltage is close to zero. DTC P0696 is triggered when the PCM detects that the voltage remains high when the cooling fan 3 is commanded on.
Symptoms & Severity of the Code
Some symptoms of a P0696 code may include:
If the conditions necessary to trigger this DTC are present, there is a high likelihood of the engine overheating due to non-operational cooling fans. Therefore, caution should be exercised when driving the vehicle under such conditions, and the issue should be addressed as soon as possible.
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
In my experience, a faulty cooling fan relay is the most common cause of this DTC. One simple way to check the relay is to locate it and visually inspect other relays that are identical to it. Then, switch the two relays. Clear the codes and operate the vehicle. If the code does not reappear, replace the relay. If the code does reappear, there may be a potential issue with the PCM.
Note: It is crucial to ensure that the relay being switched is identical in every aspect. Installing an incorrect relay could cause damage to the PCM. Nissan, in particular, has relays that may appear similar but have slight differences in color and can damage the PCM if mistakenly installed.
