What are the results of the GM EGR valve test?
Check engine light (CEL) will be shining nice and bright. P0401 EGR System Flow Insufficient. P0403 EGR Solenoid Control Circuit. P0404 EGR Open Position Performance. P0405 EGR Position Sensor Circuit Low Voltage. Rough idle. Really bad gas mileage.
What are the codes for GMC check engine lights?
P1245Intake Plenum Switchover Valve P1250Early Fuel Evaporation Heater Circuit P1257Supercharger System Overboost P1258Engine Coolant Overtemperature – Protection Mode Active P1260Last Test Failed SCC Or Theft Detected, Vehicle Immobilized
How many wires are in an EGR valve?
There are 5 wires sticking out of the EGR valve’s connector, in this section we’ll explore what each one does. Most of the EGR valves will have the letters A thru’ E molded onto the EGR valve’s connector. I’ll be using these same letters for the circuit descriptions below: Ground circuit for EGR valve solenoid. Gray with Black stripe wire.
Where is the trouble code on a GMC?
When retrieving GMC trouble codes with an OBD II scan tool, proceed as follows: 1. Connect scan tool to the 16-pin data link connector (DLC) located underneath the steering column. The connector may have a removable cover. 2. Turn the ignition on.
What should I do if my EGR valve is blocked?
You will need to clean the EGR valve of the blockage using the following steps: Disconnect battery. Remove sensors or clips. Loosen bolts holding the EGR valve. Use a EGR or Carburetor Cleaner to spray the valve and hoses. Reconnect the battery.
What should I do if my ECM goes bad?
It triggers a series of different codes to pinpoint the problem and restore optimal engine performance. However, when everything in the car seems fine, but your check engine light is still on, the issue might be a failing ECM. The mechanic will also look for problems in the wiring harness.
How does the ECM know when EGR is flowing?
When EGR is flowing, the pressure will rise in the hose connected below the orifice and drop in the hose connected above it, thus the Engine Controller (ECM/PCM, etc.) can determine if EGR is flowing and how much.
What happens if the EGR valve is not working?
This provides the correct amount of exhaust gas recirculation for different operating conditions. This system does not allow EGR at idle. A failed or malfunctioning EGR system can cause engine spark knock, sags or hesitation, rough idle, engine stalling and increased emissions.
Why is EGR important to the p0401 code?
Usually on an OBD2 system that sets the P0401, the ECM/PCM must see the failure on two consecutive trips before it will permanently set the code and trigger the Check Engine Light. The EGR system is important because it reduces emissions by allowing burnt exhaust gas to flow back into the engine.
How can I tell if my ECM is failing?
When an issue arises, the ECM will log an error code that lets you know the source of the problem. This can be advantageous since you can determine the exact cause of failure. It can also be inconvenient since you’ll need a mechanic with an expensive computer to read the error code. What Would Cause ECM Failure?