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What started as a check engine light has grown into a potential $300+ repair. secondary air bypass (diverter) valve
I purchased this vehicle at 95k miles in late July 2015. First its engine coolant thermostat wasn't working (separate story). The repair was covered under a purchase warranty, so that saved ALOT of headaches and money. To diagnose that, I used a OBD 2 scanner to watch the engine coolant temp in real time to verify that the temperature was not reaching operating temperature.
Back to this story. Around 98K, the check engine light went off on the dash. I used my OBD 2 scanner to pull the codes off and since then, have cleared the light each time it comes on. The two main codes are P0491, and P0410. These two codes specify as a "secondary air injection system malfunction". HERE"S THE REPAIR PART.
With my emissions expiring in April 2017, and new information I have learned off, I am in the process of making the repair(s). The two parts that are likely to be replaced are the Air Pump, located below in front of the engine, AND OR , the "secondary air bypass (diverter valve).
First off, I did a full removal AND installation of the diverter valve currently on the car (30-1hr job time frame) just to see how difficult this repair could be. It was MF because of wiring, and not a lot of room to work with, so for those with large hands good luck.
Both parts are expensive, but the secondary air bypass valve is a rare part, I called a local NAPA store, Autozone, and Advance Auto Parts, and NONE HAD IT. I finally called a local ford dealer, and they had it in stock. TO SAVE SOMER RESOURCES, I went onto rockauto, and found the part for MUCH MUCH LESS.
Overall, the main cause according to the youtube video, two of them, are pointing to a $.20 rubber gasket that has failed, and another $5 metal disc inside the diverter valve. The rubber gasket wears out, basically dries out, thus allowing air to move freely. AND the metal disc becomes stuck, not a free floating in a UP-DOWN motion.
I will also rule out the air pump because its a more difficult task to replace, more expensive, time consuming......etc.
Here are links to the videos. One video is 25min+ of a full diagnosis, the other video is a quick explanation of which part(s) that are likely to be replaced WITH a how to diagnosis a bad air pump.
Simsbury, CT, US
Thermostat replacement. Out of warranty so did it myself.
Ford Part/Motorcraft #rt1193 from RockAuto
Definitely a PITA to fix!
- Dillon H.,
The Woodlands, TX, US
Check engine light came on as I was driving across town. I immediately pulled over to auto zone and had them check it on their machine. The diagnosis came back that it was low on coolant. So I bought some and took it home, topped it off in the morning. Bam, check engine light went off.
About a week later, the check engine light came back on. I took to my mechanic, he put it on the machine and advised me it was a bad thermostat. Ok....not so bad right? Im thinking like 50-100 bucks....wrong. It would have been had it not been for whatever stupid designing engineer decided to shove everything under manifolds and plates under the hood which takes about 3-4 hours to get to. They basically had to take off my engine manifold to get to the thermostat.
The car was fine after it was fixed. The price at $350.00 wasnt so bad to fix it, but it was definitely an inconvience.
Wilmington, NC, US