SOLVED

Accord 04, 2.4L Ex, AT. CEL on, not blinking. CEL also goes away after a bit of driving, (15-30 mins.) I think that this issue has something to do with the temperature, as the issue started when winter did, car only has the shutting off problem for the couple startups it has that day, also car only shuts off when idling.

Has thrown up 2 codes 7 days ago, being
P0122(7-1) - TP SENSOR (A) VOLTAGE LOW
P0107(3-2) - MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR CIRCUIT VOLTAGE LOW

I was really busy and wasn't looking to troubleshoot too much so I just bought and replaced both parts, I cleaned out the throttle body while I was at it, and ensured that the new tp sensor was positioned as close as I can to .5v, (It was either getting .49 or .51 so i left it at .51).
After the replacements and clean, the idle was now smooth where as before it was aridic, however the problem did not go away, that being the engine shutting off when first starting it, and it sometimes shutting off when the car is stopped at a light for example.

After the swap the tp sensor code stayed the same, but the map code changed to:
P0122(7-1) - TP SENSOR (A) VOLTAGE LOW
P0108(3-2) - MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR CIRCUIT HIGH VOLTAGE

That was around 3 days ago, I'm thinking that the spark plugs might be at fault so I ordered all the tools I need to replace them off amazon, and they should be coming today. I started the car up this morning, and was met with the car shutting off, and a new code
P0122(7-1) - TP SENSOR (A) VOLTAGE LOW
P0108(3-2) - MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR CIRCUIT HIGH VOLTAGE
P0452(91-1) - FUEL TANK PRESSURE (FTP) SENSOR CIRCUIT LOW VOLTAGE

At this point I'm really not sure what to do. I've looked up other forums, and they recommended checking the voltage of the sensors which I've done, the only real issue I might have found is the MAP sensor reads 2.5 V, instead of the 5.0 V when the engine is off, but other than that everything else seems to be fine, TP sensor goes up to 4.5 volts when full throttle, and FTP sensor is currently at 2.45 V.

I have a good OBD2 scanner, so I'm able to provide the pdf of the report, which is attached.

As of right now I'm just stuck and would appreciate any tips I could try. Again, I'll be checking the spark plugs today but if they turn out to be fine then I wouldn't know what to do afterwards.

P.S I had replaced the map sensor first, and during the 4 days it took for the TP sensor to get here the car was running on limp mode, and fuel economy was terrible, after the TP sensor replacement and throttle body clean it seemed limp mode was gone.

Thank you.

 

I doubt spark plugs are the issue.

Was any work done on the car not long before this happened?

P0122 has a ton of steps troubleshooting in the shop manual, so a bunch of items can cause the code. You may want to get the pdf. I got one from automanualsource.com for ~$22 and is worth the money.

Is the range for throttle position sensor 0.5V when throttle is closed and 4.5V when the throttle is wide open? You should be able to do this with the engine not running and key in the II position.

Does your scanner store freezeframe data with error codes? This gives the sensor readings when the check engine code is set.

Those sensors have a 5V reference signal that might be getting pulled to a different voltage and messing up the sensors. The TPS 5V reference is the middle wire. The 5V could be dropping out when driving.

 

Thank you for your response, you were right, I just bough Laser Iridium plugs and no difference, also used seafoam as I heard dirty fuel injectors may be the issue but again no difference.

No work was done to the car before this happened.

I've noticed that the range for the throttle position sensor is between .51 - 4.5+ depending on how hard you press down on the throttle. I don't think this is really an issue because I doubt the sensor going above 4.5 (has never happened as I've never completely floored the gas) would be an issue.

If I've understood what you've said correctly, then yeah but I personally have to press freeze frame exactly when it happens, I can also record the readings and hope that the car decides to shut off when it happens.

As for the 5V reference, I'll double check both the TPS and MAP sensor, but last I checked (4 days ago) they were both at 5v.


This morning the car shut down 3-4x, and I noticed something weird, when the car would shut off and display all the lights, if you started it up instantly, it would have pulsing idle issues at around 500-600rpm, and it would be stuck there. But if the car shuts off, and you completely turn off the ignition, and turn it back on it would idle normally (1.5k idle then drop since it was cold outside). I think this may have something to do with the issue, but I'm not sure what it would mean sadly. However in both instances the car would shut off shortly after. Also I've now learned the shut off's happened regardless of car temperature, until it exactly hits operating temperature. (A bit below half way on the temperature reading on dash)

My next steps are checking the ON position Voltage for both the TPS and MAP, and also recording data when I first start the car, as the moment it would shut off I'd be able to go back through the recording frame by frame.

Lastly, I dont really know what to do for the EVAP sensor, code P0452, I'm not going to replace it since I dont think the sensor is at fault here.

 

Freeze frame data is stored by the PCM when an error code is set. You code reader should be able to look at that data. Just google your scanner to see how (or if) you can find that data.

I wouldn't worry about the EVAP.

This is difficult, because you are going to have to catch the problem when it is happening. Maybe your scanner can plot/chart some data. I'd probably chart battery voltage, your 5V signal (if possible), fuel trims (long and short term), throttle position sensor, map sensor. See if something obvious changes when your car acts up.

Can you measure fuel pressure on your car?

 

Apologies for the delay, I've still not been able to find the solution. Where I live has now gotten a bit above the 0*C and it doesn't happen anymore, meaning it definitely has something to do with temperature, It has stalled however after being fully warmed, and this happened on a steep angle, so maybe there's a connection there? If I ever do find the solution I will make sure to update this thread.

P.S I did take it into the dealer to ask for their opinion, they told me it may be the alternator??? After testing the alternator, it was perfectly fine, and I haven't ever experienced dimming headlights or electric problems. I have noticed that the auto tensioner was a bit due, (still within the line but barely by a mm). I'm replacing it today so hopefully that was the issue.

 

Update 2.0, took it to a second mechanic, couldn't find what was wrong, suggested that I maybe switch to 0W-20 oil since its an older 2.4L, so I did and now the car stalls 2x more than normal during cold starts which makes no sense to me, Considering 0W-20 is meant to be better for winter weather. I am really stumped, the car also takes far longer to warm up now, and the heater is far weaker even when the car is fully warmed up.

Any suggestions? I've had the same codes, being P0122 P0108, I've now cleaned the Automatic Throttle body thing, although not to well since I couldn't unscrew it, but again no difference.

I'm a perfectionist so although the car is older, I cant stop trying things until its fixed.

 

I'd probably drain the 0w-20 and use the weight oil recommended for your car. I don't think this will solve your problem.

Were the sensors you installed OEM or aftermarket sensors? If you have the original map sensor, try reinstalling it.

 

Sensors I installed were OEM, I've spoken to a mechanic with 40 years of experience and he said 9/10, its the fuel injectors, I have run sea foam, however he says that it'd be best to get them professionally cleaned, I'm going to try out carb cleaner first directly into the injectors, and see if that helps.

Hopefully this solves the issue

As for the 0W-20, I've noticed the car now runs a lot smoother, And since this is my third oil change within 2 months, I honestly may leave it. Do you think it'd cause issues? I've ofcourse researched online but could not find anything related to oil type and how long/ how hot the car heats up to.

Thank you for your help thus far

 

Changing the oil isn't the fix to this problem. I'd recommend returning to the recommended oil on the next oil change.

The map and tps codes are troubling. Did the new map sensor come with a new o-ring? Was the old o-ring removed when you removed the old sensor? I'm trying to think of simple things to check to eliminate causes for the CEL.

 

I have found the problem and I'm quite disappointed at how long it took, I am with 99% certainty that after all of my hours of research over the past couple months, and hundreds dumped into the car that it is the IACV, I had cleaned the throttle body, and wasn't able to get to the IACV correctly so I just sprayed the holes with MAF cleaner, twice now, the third mechanic I spoke to had lead me in the right way, in order for a car to keep running it needs fuel and gas, spark of course was obviously ruled out as the car started perfectly, and I had replaced all coils, and sparkplugs with the highest quality I could find. Thinking about it deeper it was obviously not gas as the car did start up, and you could smell gas when opening the hood...

hmm smelling gas when you open the hood, and we know that sparks are working? Meaning Air is the problem,

It was literally hinted at by the codes but I was too inexperienced to see it,
P0122(7-1) - Throttle Position Sensor, Low Voltage
P0107(3-2) - Manifold Absolute Pressure (MAP), Voltage Low

(So something to do with the throttle, and the air pressure after the tb? and only at idle? jhee wonder what controls the throttle at idle)

I'm quite angry at how long this took to solve, and how many mechanics I had to go through to even get a hint, I hope that someone find this in the future and is able to save time, as all other threads containing these codes died off without anyone giving a valid answer.

Now, if you have this problem one way to know for sure if it is 100% the IACV, (Idle Air Control Valve) is if when you start the car and it runs poorly, and you know its about to die since it dies 10x per morning, try holding the throttle to 2.5k ish, only do this after the first start of course as you don't want to damage the engine, IF the engine continues to run, (although very poorly with misfires and knocking) then you know its something to do with the Throttle Body area, so try cleaning the TB, if that doesn't fix the problem then its most likely the IACV.

Another thing I've noticed which I'm going to call IACV VTEC is that the IACV completely disengages after 2.7k-3k~ rpm, lol, so again, if you rev past this and the car runs perfectly fine then you know for certain its the IACV.

Now that the problem is known, I've tried cleaning it, and letting it sit in MAF cleaner but both did nothing (since this was while the IACV was attached to the throttle body meaning I couldn't open the valve to perfectly clean it), so for your case either completely remove it from the throttle body, (Making sure to use a JIS #2 screwdriver to not strip anything as I did) and clean it, or just go to a U-Pull yard and buy the entire throttle body for like $50, a good indication of a good throttle body to take would be that theres minimal carbon buildup.

And that concludes the only form on the entire internet with P0122 and P0107, and an actual answer. Hope this saves you time.

P.S I've seen tricks where you got a small hammer while the engine is running poorly, and lightly tap the IACV and that would make the car run perfect again, confirming the IACV is the problem, however It did not work for me.

P.S 2.0, Obviously check the MAP and TP sensor with a multimeter to make sure everything is running as it should before going for the IACV, I sadly don't remember what to look for as its been 7 whole months since I've done it... Luckily you're able to find your answer on Youtube since its a covered topic.

P.S 3.0, Do not torch the IACV as I did while trying to get the screws out, the body is made of aluminum and you'll end up heating the entire throttle body which is bad since I've read that some of the IACV is made of plastic, also the gasket inside may melt, not 100% sure tbh. If a #2 JIS screw driver isn't working, try tapping the screw straight on, and adding penetrant, and gently seeing if itll move, if it does great unscrew it a bit, add more penetrant, and screw it back in again, going back and forth (would take 2-3 minutes ish). you mostly likely wont have it rusted completely as I did, since I'm in the salt belt.

Good luck

And special thanks to PAhonda who has taken the time to reply over the past couple months,