Engine code p0303 - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum

dbmazda · 10-14-2012, 10:22 PM

Hello
Ive got 04 mazda 6 wagon v6 . The code talks about a misfire . I replace the coil pack . Thinking that would fix the problem . Which it did for about 60 miles and light back on with the p0303 code again. Im think fuel injector . Is there other thing i should be looking at ?

Thanks
David B

ctmazda · 10-14-2012, 10:34 PM

Spark plugs spark plugs spark plugs! Well plug, but they are cheap so you might as well replace them all while you are at it.

P.S.- Did you reset the ecu when you replaced the coil? Aka disconnecting the battery?

This is a 100% must when doing any type of electrical/engine work, especially when working with engine diagnostics/codes.

Also, where exactly was the coil you changed? Many people have the cylinder order messed up on the v6s.

Sent from my iPhone using Autoguide

Mr.Smoke · 10-14-2012, 10:34 PM

Welcome to the club!!

Spark plugs & all ignition coils.

dbmazda · 10-14-2012, 11:05 PM

Hello
I did replace all the coils and plugs .

David B

JFisher100191 · 10-14-2012, 11:13 PM

I'm going to have to disagree with unplugging it to "reset the ecu" the vehicle does thousands of self checks a minute and will only throw the code when there is an ACTIVE issue. It will retain the history code but won't have a present DTC if there is no present fault.

Mr.Smoke · 10-14-2012, 11:26 PM

Fisher i must agree with you. However, the battery should be unhooked when changing coils.

JFisher100191 · 10-14-2012, 11:38 PM

Agreed with that, anything I ever do with my car, the battery gets disconnected first. You never know when you might hit a plug or pop a fuse and cause a ton of heart ache that could have been avoided. Bit of a pain to always have to reprogram my radio stations but it's worth it in the long run.

flipper66 · 10-15-2012, 01:13 PM

there is still a retained code and the CEL will remain illuminated till the engine has several cycles of not recognizing the issue still existing. Also, the Plug itself will be saturated with fuel if the coil wasn't up to snuff, so it is going to still "have a problem" till the cleans off.

Lastly, resetting returns the ECU to the base map. When there is a code the engine pulls timing and adjust fuel trims to avoid havoc or engine damage. Once the problem is eliminated, resetting back to "all clear" is the proper thing to do.

dbmazda · 10-16-2012, 04:21 PM

Hello everyone
Here what has been done . Ive put new plugs and coils pak . Yes all 6 plug & coil paks The reason for both plug and the pak was because i got the p303 code and good change the plugs. Which is a misfire code .Also ive reset the car's computer . Ran great for about 60 miles then the p303 code came back. I put a seaform in the gas tank .It seem to be running better . But still got along way to go .

Thanks
David B

flipper66 · 10-17-2012, 12:02 PM

Possibly a very dirty injector.

did you replace the plenum gaskets when you did all this work?

10-14-2012, 10:22 PM	#1 (permalink)
dbmazda Learners License Join Date: Oct 2012 Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) iTrader: 0 reviews	Engine code p0303 Hello Ive got 04 mazda 6 wagon v6 . The code talks about a misfire . I replace the coil pack . Thinking that would fix the problem . Which it did for about 60 miles and light back on with the p0303 code again. Im think fuel injector . Is there other thing i should be looking at ? Thanks David B

10-14-2012, 10:34 PM	#2 (permalink)
ctmazda Registered User Join Date: Jan 2011 Posts: 1,571 Thanks: 353 Thanked 245 Times in 215 Posts Groans: 1 Groaned at 3 Times in 3 Posts Mentioned: 30 Post(s) Tagged: 0 Thread(s) Quoted: 193 Post(s) iTrader: 0 reviews	Spark plugs spark plugs spark plugs! Well plug, but they are cheap so you might as well replace them all while you are at it. P.S.- Did you reset the ecu when you replaced the coil? Aka disconnecting the battery? This is a 100% must when doing any type of electrical/engine work, especially when working with engine diagnostics/codes. Also, where exactly was the coil you changed? Many people have the cylinder order messed up on the v6s. Sent from my iPhone using Autoguide __________________ 2004 Mazda 6 Sport V6 MTX-*Steel Grey* MSDS Headers/Ported Intake Manifolds + 1/2" Spacer/Injen CAI/3.7L OTB/TGNY TB Spacer/Magnaflow CBE/AWR 88 Mounts/Rotora H2 Ceramic Brakes//CF Evo Hood,Grill,Eyelids,Window Visors,Mirror Covers/CAR-LED Tails/35W 5000k HIDs/55W 6000k Integrated Fogs/LED Fogs/1000w Xplōd Amp/Two 800w 12" Xplōd Subs/15% Tints/18x8.5 +50 Kazera "CF" Rims/Hankook Ventus Evo 245/40/18 Future Mods:Powermod Tuner/Custom DoubleDin/BC Coils Last edited by ctmazda; 10-14-2012 at 10:39 PM.

10-14-2012, 10:34 PM	#3 (permalink)
Mr.Smoke Love Dem Beads Join Date: Dec 2011 Location: Kitchener, ON Canada Posts: 5,748 Thanks: 813 Thanked 867 Times in 732 Posts Groans: 1 Groaned at 4 Times in 4 Posts Mentioned: 166 Post(s) Tagged: 2 Thread(s) Quoted: 773 Post(s) iTrader: 0 reviews	Welcome to the club!! Spark plugs & all ignition coils. __________________ Smoke's Build --- Ontario Meet Thread --- Ontario Members Thread --- VOTE FOR 6OTM

10-14-2012, 11:13 PM	#5 (permalink)
JFisher100191 Registered User Join Date: Sep 2012 Location: Lynchburg, VA Posts: 545 Thanks: 28 Thanked 94 Times in 77 Posts Groans: 1 Groaned at 2 Times in 2 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s) Quoted: 33 Post(s) iTrader: 0 reviews	I'm going to have to disagree with unplugging it to "reset the ecu" the vehicle does thousands of self checks a minute and will only throw the code when there is an ACTIVE issue. It will retain the history code but won't have a present DTC if there is no present fault. __________________ '12 Mazda 6i Sport: Smoked markers Blacked out trim and emblems OEM Spoiler with LED 3rd brakelight Many more to come

10-14-2012, 11:26 PM	#6 (permalink)
Mr.Smoke Love Dem Beads Join Date: Dec 2011 Location: Kitchener, ON Canada Posts: 5,748 Thanks: 813 Thanked 867 Times in 732 Posts Groans: 1 Groaned at 4 Times in 4 Posts Mentioned: 166 Post(s) Tagged: 2 Thread(s) Quoted: 773 Post(s) iTrader: 0 reviews	Fisher i must agree with you. However, the battery should be unhooked when changing coils. __________________ Smoke's Build --- Ontario Meet Thread --- Ontario Members Thread --- VOTE FOR 6OTM

10-14-2012, 11:05 PM	#4 (permalink)
dbmazda Learners License Join Date: Oct 2012 Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) iTrader: 0 reviews	Hello I did replace all the coils and plugs . David B

10-14-2012, 11:38 PM	#7 (permalink)
JFisher100191 Registered User Join Date: Sep 2012 Location: Lynchburg, VA Posts: 545 Thanks: 28 Thanked 94 Times in 77 Posts Groans: 1 Groaned at 2 Times in 2 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s) Quoted: 33 Post(s) iTrader: 0 reviews	Agreed with that, anything I ever do with my car, the battery gets disconnected first. You never know when you might hit a plug or pop a fuse and cause a ton of heart ache that could have been avoided. Bit of a pain to always have to reprogram my radio stations but it's worth it in the long run. __________________ '12 Mazda 6i Sport: Smoked markers Blacked out trim and emblems OEM Spoiler with LED 3rd brakelight Many more to come

10-15-2012, 01:13 PM	#8 (permalink)
flipper66 banana boat. Join Date: Aug 2004 Location: lake Mary, Florida Posts: 6,203 Thanks: 63 Thanked 778 Times in 682 Posts Groans: 2 Groaned at 44 Times in 40 Posts Mentioned: 20 Post(s) Tagged: 1 Thread(s) Quoted: 117 Post(s) iTrader: 1 reviews	there is still a retained code and the CEL will remain illuminated till the engine has several cycles of not recognizing the issue still existing. Also, the Plug itself will be saturated with fuel if the coil wasn't up to snuff, so it is going to still "have a problem" till the cleans off. Lastly, resetting returns the ECU to the base map. When there is a code the engine pulls timing and adjust fuel trims to avoid havoc or engine damage. Once the problem is eliminated, resetting back to "all clear" is the proper thing to do. __________________ if you need a new V6 engine look here

10-16-2012, 04:21 PM	#9 (permalink)
dbmazda Learners License Join Date: Oct 2012 Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) iTrader: 0 reviews	Hello everyone Here what has been done . Ive put new plugs and coils pak . Yes all 6 plug & coil paks The reason for both plug and the pak was because i got the p303 code and good change the plugs. Which is a misfire code .Also ive reset the car's computer . Ran great for about 60 miles then the p303 code came back. I put a seaform in the gas tank .It seem to be running better . But still got along way to go . Thanks David B

10-17-2012, 12:02 PM	#10 (permalink)
flipper66 banana boat. Join Date: Aug 2004 Location: lake Mary, Florida Posts: 6,203 Thanks: 63 Thanked 778 Times in 682 Posts Groans: 2 Groaned at 44 Times in 40 Posts Mentioned: 20 Post(s) Tagged: 1 Thread(s) Quoted: 117 Post(s) iTrader: 1 reviews	Possibly a very dirty injector. did you replace the plenum gaskets when you did all this work? __________________ if you need a new V6 engine look here

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