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Discussion Starter · #1 · (Edited)
Ford Focus 06 CEL PO491 & PO410 (new problem?)

Check engine light came up on my Ford Focus zx5 2.0. Codes pulled were po491 and po410. Found the EVR solenoid wasn't working properly/at all and changed the solenoid and the car sounded strong when the engine started. 3 days later and the check engine light came back up. Same codes pulled. Car doesn't sound weird at start up like it was prior. Any idea? Checked the tubes and all of them are on with no cracks. Thanks in advance.
 

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has a screw loose
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Posted via FF Mobile When you replaced the part did you disconnect the negative side of your battery for about 10 to 15 mins so the Ecu could reset and learn your driving habits?
 

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Discussion Starter · #3 ·
Posted via FF Mobile When you replaced the part did you disconnect the negative side of your battery for about 10 to 15 mins so the Ecu could reset and learn your driving habits?
I didn't do that... Should I do that now? I've driven about 10 miles on it.
 

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Posted via FF Mobile I would do it even though you've driven it. Just remember after you hook your negative side back up to let it idle for around 5 minutes then after that take it out for about a 20 to 30 minute drive so the Ecu can relearn its new parameters .
 

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Discussion Starter · #6 ·
Disconnected the negi side of the battery, waited 20 mins and reattached it. Let it sit in idle for 5 mins and drove for 20 minutes. Car sounds great but will wait and see.
 

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Discussion Starter · #7 ·
Car starts fine then sounds like it's going to die (makes a quiet/low noise) then comes back strong (I've only driven about 20 miles since doing like you said.) Check engine light hasn't came back on and while driving the car sounds fine. Even when idol at a light it sounds normal. Not sure what to check next.
 

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P0410 SAI (Secondary Air Injection) System Malfunction
P0491 SAI System Insufficient flow

FWIW, I've read the problem may lie with the diverter valve on the air injection pump. The pump itself, pump relay or check valves may also be a cause of the codes. Not sure what the effects on engine performance are.
 

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Discussion Starter · #10 ·
I went through all the lines again for cracks or if they were off and found nothing.

Car still starts strong, then sounds like it's struggling for air, then after about 4-8 seconds will comeback strong. After driving somewhere the car will start fine and not show any of the problems above.
 

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Discussion Starter · #12 ·
Bump. Replacing the TPS this week. Hopefully it will fix the weird idle thing that's happening when I start the car.
 

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I don't have a whole lot of experience with SAI systems since it's not required here. I can't even make an educated guess at what in the SAI system would cause idle to go down. All it should do is force air into the exhaust to improve catalytic efficiency. The air pump is driven by the engine, but I'd think you'd hear some horrible noises to alert you if the pump itself was the problem.

Sorry I can't be more help, I just wanted you to know you're not being ignored.
 

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Discussion Starter · #14 ·
I seem to be having at least two problems (Still haven't located the CEL problem po491 and po410). Car is now making a weird mid range noise after start up. Also when the car is cold it starts up normal and now almost dies out and comes back strong. The car still drives well though. One mechanic said the start up problem is the TPS.

Also before I order the TPS, do I need the whole Idle Air Control (IAC) Valve or just the TPS? (tps is what's cracked) I don't seem to remember screws on the top of the unit to allow that to be removed by itself.
 

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If the TPS is cracked, then yes you need a new one. The IAC can be removed and cleaned instead of replaced, and that should solve your problem if it is a cause. If your car didn't have SAI, the IAC is what I'd have pointed to for a start idle issue.

TPSs that are bad typically cause other problems- and I'd think one that was cracked would also. You'll sputter on hard acceleration, and sometimes it will stall when slowing down quickly. It will only throw a DTC when it fails the self test. The TPS is inactive during startup idle, but if for some reason it was giving a false input reading the PCM might be adjusting the IAC to compensate.

For IAC symptoms, I typically recommend removal and cleaning first before replacement. Sometimes that will save you $50. If you search a parts supplier online like Autozone, then you'll see a picture of the IAC, and that will help you determine what it is. It's located just behind the throttle body on the intake manifold.

Another suspect- IMO- is the 100k mile air cleaner. I don't like that thing, and neither does anyone on here. It was a bad idea that Ford did from 03-07 on the Duratec engines. That's what you have, and was the only engine available 05-07. Most enthusiasts remove it ASAP, and replace it with a cold air intake or short ram intake using a cone air filter. You can also simply remove the air filter element itself, and put a 3.5" cone air cleaner on the end of the MAF tube- which is what I did for many years. That's the cheapest way to remove it. Most manufacturers like K&N or FSWerks have 50 state legal certifications. In your case, I'd test it first. Follow the procedure located in the owner's manual, and at this time I wouldn't replace it unless it failed the test. I have seen where damage to the air cleaner from road debris caused idle and running issues- but you only have the idle issues.

FYI: IACs and TPSs are 2 parts that don't usually throw DTC codes while the vehicle still runs.

Please let us know if any stupid things have been done to your car- like adjusting screws on the throttle body. Also, it is typical in the winter for there to be some sticking of the gas pedal. To alleviate that problem, clean your TB the next time you have the air intake off the engine- like if you replace the IAC or TPS. If you do replace the TPS, then afterwards remove the neg batter terminal for 5-10 mins, replace the terminal, start the car, and allow it to idle for at least 5 minutes after the engine drops out of cold start. This will reset the A/F ratio and the PCM fuel map. Expect a possible small drop in fuel economy for 2 weeks after reset until the car re-learns the fuel map.
 

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Discussion Starter · #16 ·
Thanks for the reply. That was a little too detailed for my begginer car knowledge haha. Checked the IAC and the whole thing needs to be replaced since the tps/iac is one part (not able to switch out just the tsp.) Will check the air cleaner once I locate it. And I don't believe anyone's messed with the TB.
 

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Just so you don't over tighten anything , I looked on my Alldata sub for the torque specs and this is what I have .

Throttle Position Sensor 10 NM (89 lb-in)

Idle Air Control 4 NM (35 lb -in)
 

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Checked the IAC and the whole thing needs to be replaced since the tps/iac is one part (not able to switch out just the tsp.)
I'm not sure what you're looking at, but I have the same engine, and the TPS is not the same part as the IAC.

Here's a pic of the IAC


Here's a picture of the TPS


The TPS is located at the other end of the throttle plate shaft from where the cables connect. It rotates with that shaft. In fact, you must be careful when installing a TPS to be sure that you line the TPS up with the shaft before screwing it down. A common mistake is to line up the screw holes, and bolt it in, but if the TPS is installed correctly, it will be tilted towards the air intake, and then have to be rotated back to line the screws up. It should fit perfectly flat against the TB without any force.

The IAC just bolts on and off.

What is this part that you think is an IAC and TPS combined?
TPS= throttle position sensor
IAC= idle air control (valve)
 

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Discussion Starter · #20 ·
Well damn. I said it was one part because the last mechanic I went to said the TPS and IAC needed to be replaced. And the part he pointed at was just the IAC... I guess.

The top part of my IAC is cracked where the plug meets the female adapter.

Now I will locate the TPS and see from there.
 
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