|Code||Fault Location||Probable Cause|
|P06DE|| Engine Oil Pressure Control Circuit Stuck On |
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Table of Contents
- What Does Code P06DE Mean?
- Where is the P06DE sensor located?
- What are the common causes of code P06DE?
- What are the symptoms of code P06DE?
- Get Help with P06DE
What Does Code P06DE Mean?
OBD II fault code P06DE is a generic trouble code that is defined as P06DE – “Engine Oil Pressure Control Circuit Stuck On” or sometimes as P06DE – “Engine oil pressure control – control circuit malfunction – ON signal” and is set when the PCM (Powertrain Control Module) detects a defect or malfunction in the circuits that control and monitor the operation of a dual-pressure oil pump.
NOTE: Code P06DE may sometimes be present along with code P0520, with the latter code indicating a malfunction of or defect in the circuits of the oil pressure switch that monitors the actual engine oil pressure at all times, as opposed to a problem with the solenoid (and its associated wiring) that switches the oil pump between high and low-pressure modes. In most such cases, resolving code P0520 will usually, but not always, also resolve code P06DE.
Unlike older engines whose oil pumps delivered pressurized oil at a pressure that was determined by both the pumps’ capacity and the engine speed, most modern engines now have oil pumps that can be switched to pressurize engine oil to different levels to suit changing engine operating conditions. Here is how this works in practice-
The problem with old-style oil pumps is that although they deliver copious amounts of highly pressurized oil to moving engine parts at high engine speeds (when engines develop large amounts of power), the amount of energy an oil pump requires to force oil through small clearances between moving and sliding parts is relatively small compared to the engine’s total power output.
However, since old-style oil pumps deliver pressurized oil at fixed rates, the amount of energy an oil pump requires to pump oil around an engine that is running at low to moderate speeds remains the same, although the engine is now developing considerably less power. As might be expected, this greatly increases the total parasitic power loss an engine experiences, and while burning more fuel can overcome parasitic power losses, burning more fuel causes more harmful exhaust emissions.
So to remain within maximum allowable exhaust emission levels/limits, engineers developed oil pumps that deliver high-pressure oil at high engine speeds when engines require high levels of effective lubrication, and oil at a slightly lower pressure when engines are running at lower speeds and under light load conditions.
As a practical matter, the object of this oil pressure strategy s to reduce the parasitic power losses an engine experiences at low speeds to reduce exhaust emissions at low engine speeds since the engine no longer needs to burn more fuel to overcome high levels of parasitic power losses.
We need not delve into the technical complexities of how oil pumps vary their output beyond saying that in some designs, a control solenoid bleeds of excess oil pressure to reduce parasitic power losses, while in most other designs, various mechanisms change the pump’s interior geometry to either reduce or increase the pressure the pump develops. It should be noted that in both designs, the mechanisms that change the oil pump’s output is controlled directly by the PCM.
It should also be noted that to increase the lubrication system’s overall efficiency, most modern engines now use multiple oil pressure sensors that are located at different points around the engine to provide the PCM with an improved “big picture” sense of how efficiently (or otherwise) the engine is being lubricated at all times. Nonetheless, while the advent of dual pressure (aka dual-stage oil pumps) has improved engine lubrication at low engine speeds while saving fuel at the same time, modern engine lubrication systems are highly complex systems that can go wrong for any number of reasons.
Regardless of the cause(s) of engine lubrication systems, though, most modern PCMs can detect a deviation from the desired oil pressure at almost any point in the lubrication system in about 250 microseconds (0.25 of a second) and in most cases, remedial action will follow almost instantly to prevent or limit possible engine damage.
In practice, such remedial or preventative actions could include, but may not be limited to-
- setting one or more trouble codes
- illuminating a warning light
- initiating a fail-safe or limp mode to protect the engine
- preventing the engine from starting again after an engine shutdown until the fault is found and corrected
Where is the P06DE sensor located?
This image shows the underside of a Jeep Wrangler engine with the oil pan removed for clarity. In this view, the red arrow indicates the oil pump, while the yellow arrow indicates the oil pickup filter screen. It is worth noting that many Jeep and other diesel Chrysler models are notorious for the frequency with which these screens become clogged with carbon and other deposits, which almost invariably causes code P06DE and the closely related code P06DD to set.
Note that in many cases, it is necessary to remove the engine from Chrysler products to remove the oil pan to access the oil pump, which is not a procedure recommended for non-professional mechanics. Therefore, we strongly recommend that you seek professional assistance with diagnosing and repairing oil pump issues, regardless of the affected vehicle’s make or model.
What are the common causes of code P06DE?
The potential causes of code P06DE are many and varied, but note that the list of potential causes presented here is neither complete nor exhaustive because some possible causes, such as poor quality engine oil or a lack of regular oil changes can produce different effects on different vehicle makes and models. Nonetheless, some common causes of this code could include one or more of the following-
- Dirty, degraded, or contaminated engine oil
- The use of incorrect or unsuitable oil grades and/or oil formulations
- Overheating of the engine
- Insufficient oil flow that is caused by restrictions anywhere in the lubrication system, but most notably, restrictions of the oil filter screen on the oil pickup tube in the oil pan
- The use of an incorrect, unsuitable, or substandard aftermarket oil filter
- A defective or malfunctioning oil pressure control solenoid
- A defective, or malfunctioning Intake Air Temperature sensor (The PCM uses information from this sensor to calculate oil pressure strategies based on the oil’s temperature as a function of the ambient temperature)
- A failure to reset the oil life monitor after a previous oil change
- An excessive number of DPF (Diesel Particulate Filter) regenerations within a specified period may cause this code to be set on some diesel vehicles, and most notably on Chrysler products with diesel engines
- Excessively high or low oil levels in the engine
- Damaged, burnt, shorted, disconnected, or corroded wiring and/or electrical connectors anywhere in the engine’s lubrication system
- Corrupted programming in one or more control modules, including the PCM
- A defective or malfunctioning Engine Speed Sensor
- A defective or malfunctioning Engine Coolant Temperature Sensor (The PCM uses information from this sensor to calculate oil pressure strategies based on the oil’s inferred viscosity as a function of the engine’s temperature)
- A failed or failing PCM, but note that since this is a rare event, the fault must be sought elsewhere before any control module is reprogrammed or replaced, but note nevertheless that installing PCM software updates will often resolve this code definitively
What are the symptoms of code P06DE?
The most common symptoms of code P06DE are largely similar across all applications and could include one or more of the following-
- Stored trouble code and an illuminated warning light
- In some cases, and depending on the nature of the problem, multiple trouble codes may be present along with code P06DE
- In most cases, the PCM will initiate and maintain a fail safe or limp mode until the problem is corrected
- Also, in many cases, the PCM may prevent the engine from starting to prevent engine damage
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