PACCAR MX (2004 Emissions) Fault Code: P171B EGR Flow Response - Decrease Too Slow - EcuForce Truck (2024)

FAQs

What is the code for the Paccar EGR malfunction? ›

Paccar p1515 egr malfunction P1495 and p1496.

This fault code indicates a communication issue between the EGR valve and the ECM. The most likely causes of this issue will be a faulty EGR valve or an issue with the wiring.

Two key components of the Paccar diesel engine are the Exhaust Gas Recirculation (EGR) and Diesel Particulate Filters (DPF). The EGR is designed to reduce the exhaust emissions of diesel engines. It achieves this by diverting exhaust gas back inside through the EGR to be mixed with the air intake.

If your vehicle has a faulty EGR valve, it might still be safe to drive for a short period, especially if the issue doesn't significantly impact performance or safety. However, driving with a malfunctioning EGR valve can potentially affect your vehicle's emissions, performance, and fuel efficiency over the long run.

Inspect the EGR valve and tubing, then clean to remove any deposits. Check the voltage at the DPFE and compare to standard values listen in your owner's manual. Swap out the DPFE sensor, preferably with a high-quality or OEM model. Replace the EGR valve if the problem persists.

Error code P0700 signifies that a malfunction has been detected in your vehicle's transmission controls. Most modern automobiles feature a specific control module as it relates to the vehicle's automatic transmission. This module is known as the Transmission Control Module (TCM).

Diagnostic trouble code (DTC) P1516 stands for “Throttle Actuator Control Module Throttle Actuator Position Performance.” This code is set when there is a problem with the TAC module.

A logged P0638 code means that the PCM has detected that the throttle actuator is not in the right position. A faulty throttle body assembly, defective throttle position sensor, wiring issues, and a faulty PCM can trigger this code.

However, the single biggest cause of failure is the buildup of carbon particles from the exhaust gases along the EGR and intake system passages. Over time this will clog tubes, exhaust gas channels and eventually the valve's plunger mechanism, causing it to either stick open or close.

How do I clear my ECU fault code? ›

Leaving the battery disconnected for a few minutes will ensure the vehicle systems will completely reset when you reconnect the battery. Secure the negative cable back to the terminal and cover it with the cap. Disconnecting the battery will clear the error codes and reset the check engine light.

It's also possible to reset a DTC by temporarily disconnecting the vehicle's 12-volt battery. Doing this shuts off power to the computer that stores the code, clearing it from its memory.

In most cases, successfully repairing the issue that caused your light to come on will cause the check engine light to turn off automatically—but only after 10 to 20 “cycles”. A cycle, in this instance, refers to the process of turning the vehicle on, running it for some time, and turning it off again.

Diagnostic trouble code (DTC) P0401 stands for “Exhaust Gas Recirculation (EGR) Flow Insufficient Detected.” The code is logged once the PCM detects that there's insufficient exhaust gas recirculation (EGR) flow in the system.

That fault is for def quality tripped by the def quality sensor in the def tank.

What does OBD-II fault code P0486 mean? EGR (Exhaust Gas Recirculation) systems are used to reduce the combustion temperature, thus reducing emissions. If the engine control module (PCM) does not detect the amount of flow requested from the EGR, it will set code P0486.

The fault codes related to P1495/P1496 mean that the engine protection has been enabled causing the EGR to be disabled and the system to go into preventative safety measures. As a result, passive/active DPF regeneration is disabled as well.