HELP!!! 2007 Mazda3 AT Trans Problem
May-22nd-2017, 04:48 PM
#47
Registered User
Join Date: May 2017
Posts: 4
Mazda People,
If you are having these issues with CEL+AT light and auto trans dropping to 3rd with solenoid error codes or Uxxx codes it is almost definitely the TCM (transmission control module). DO NOT pay thousands to the dealer for a transmission replacement. It will likely not help.
I recently had same issue on my 2007 Mazda3. Dealer told me replace trans for $4k. I took car home to troubleshoot. Replaced TCM for $300 and problem solved!
The Mazda TCMs are designed poorly. They mount directly to the transmission and electronics possibly suffer thermal damage from the trans housing. There are 5 versions now. Your car probably has L34T-18-9E1A. The newest rev is L34T-18-9E1E. The only difference is probably the software. They are very simple to replace yourself and save tons of money.
Here’s what to do:
1) First go around your engine and check any electrical connections to make sure they are all seated properly, nothing loose, and no fuses blown. You may also want to check harness connectors to the ECU under the passenger floor. Also make sure all vehicle ground harness is tightly secured to the chassis. These are usually thick black cables bolted to the frame. It’s unlikely any of this is the problem but it’s the simplest thing to check first.
2) Buy a OBDII code reader. Something like this.
3) Read your error codes.
4) If you have any of these then replace your TCM.
• Uxxx – network code loss of communication with TCM or ECU
• P0753 – shift solenoid A malfunction
• P0758 – shift solenoid B malfunction
• P0763 – shift solenoid C malfunction
5) You can buy an improved refurbished TCM for $300 here. This is what I did. Or buy from Mazda part number L34T-18-9E1E. Dealers charge about $500+.
6) Install yourself like this. Or get a friend to help.
There are other less likely issues that can cause similar trans problems. If replacing TCM doesn’t solve your problem or you have different error codes than what I’ve listed then replace these sensors on top of your transmission. These are all located near the TCM:
1. Vehicle speed sensor, FN0121550 (also called speed pulse generator, transmission output shaft speed sensor)
2. Range Sensor, FN0221444 (also called auto trans gear position sensor, neutral safety switch)
3. Speedometer sensor, FN1221551A (also called vehicle speed sensor)
If after all this if you still have a problem then you could consider replacing the actual shift solenoids in the transmission or the transmission itself as a last resort. Only at this point would I consider the transmission at fault.
Good luck!
If you are having these issues with CEL+AT light and auto trans dropping to 3rd with solenoid error codes or Uxxx codes it is almost definitely the TCM (transmission control module). DO NOT pay thousands to the dealer for a transmission replacement. It will likely not help.
I recently had same issue on my 2007 Mazda3. Dealer told me replace trans for $4k. I took car home to troubleshoot. Replaced TCM for $300 and problem solved!
The Mazda TCMs are designed poorly. They mount directly to the transmission and electronics possibly suffer thermal damage from the trans housing. There are 5 versions now. Your car probably has L34T-18-9E1A. The newest rev is L34T-18-9E1E. The only difference is probably the software. They are very simple to replace yourself and save tons of money.
Here’s what to do:
1) First go around your engine and check any electrical connections to make sure they are all seated properly, nothing loose, and no fuses blown. You may also want to check harness connectors to the ECU under the passenger floor. Also make sure all vehicle ground harness is tightly secured to the chassis. These are usually thick black cables bolted to the frame. It’s unlikely any of this is the problem but it’s the simplest thing to check first.
2) Buy a OBDII code reader. Something like this.
3) Read your error codes.
4) If you have any of these then replace your TCM.
• Uxxx – network code loss of communication with TCM or ECU
• P0753 – shift solenoid A malfunction
• P0758 – shift solenoid B malfunction
• P0763 – shift solenoid C malfunction
5) You can buy an improved refurbished TCM for $300 here. This is what I did. Or buy from Mazda part number L34T-18-9E1E. Dealers charge about $500+.
6) Install yourself like this. Or get a friend to help.
There are other less likely issues that can cause similar trans problems. If replacing TCM doesn’t solve your problem or you have different error codes than what I’ve listed then replace these sensors on top of your transmission. These are all located near the TCM:
1. Vehicle speed sensor, FN0121550 (also called speed pulse generator, transmission output shaft speed sensor)
2. Range Sensor, FN0221444 (also called auto trans gear position sensor, neutral safety switch)
3. Speedometer sensor, FN1221551A (also called vehicle speed sensor)
If after all this if you still have a problem then you could consider replacing the actual shift solenoids in the transmission or the transmission itself as a last resort. Only at this point would I consider the transmission at fault.
Good luck!
I replaced the TCM on my 2008 with 198K kms on the odometer - after checking various Mazda Forums on the internet.
My friendly Kanata Mazda dealer wanted $5,200 Cndn. to replace the automatic transmission ? HUH? WTF?
On top of that, it cost #129.95 for the diagnostic check which listed the CEL codes.
My problem was eliminated with the purchase of a new L34T189E1E TCM for $550 Cndn. (...from a different Mazda dealer), and two hours of my time.
This is obviously a long term reliability problem that has plagued various years and models of Mazda with automatic transmissions.
Mazda should do the right thing, step up and issue a TSB to cover this huge long term reliability problem, instead of gouging loyal customers with expensive replacement parts,
and allowing service techs to mis-diagnose simple transmission problems !
For this reason alone, I will never own another Mazda product !
Last edited by Rivman; May-22nd-2017 at 04:52 PM.
July-9th-2017, 08:46 PM
#49
Registered User
Join Date: May 2017
Posts: 4
Maybe check with a Mazda dealer? (. . . not sure about NZ 3s ?)
November-7th-2017, 01:56 PM
#51
Registered User
Join Date: Nov 2017
Posts: 1
Hey guys, just some extra info that many of you may not be aware of concerning the infamous TCM (Transmission Control Module) failures.
If you have a Mazda 3 that is PZEV (Partial Zero Emission Vehicle) certified, then the TCM is a FREE warranty replaced item under the PZEV warranty for 15 years / 150,000 miles!!
This applies to PZEV-certified cars currently registered in the following 9 states: California, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Rhode Island or Vermont.
You can determine if you have a PZEV car by the emissions label located under the hood. However, to absolutely confirm that your faulty TCM will be covered for FREE under the PZEV warranty, it is best to call the Mazda Customer Experience Center at 800-222-5500. They will ask for your VIN and confirm that your TCM is covered. Best to give them the TCM part # for a quicker response. The part # for all 2007-2009 Mazda 3s is L34T-18-9E1A (the last letter is the Revision and can be an A, B, C, D, or E.
A Mazda warranty repair will require you to go to the Mazda dealer for the diagnosis and repair. You will have to pay for the initial diagnosis fee, but it will be waived if the TCM is determined to be faulty.
So, if you have a PZEV-certified Mazda and you have determined that your TCM is faulty and you are in 1 of the 9 states noted above, you might want to have Mazda replace it for FREE vs. you buying a new one for $500+.
Note the PZEV 15-yr/150k mile warranty applies to most all emission-related parts so be sure and check before spending your own $$ and DIY'ing any of these related parts.
If you have a Mazda 3 that is PZEV (Partial Zero Emission Vehicle) certified, then the TCM is a FREE warranty replaced item under the PZEV warranty for 15 years / 150,000 miles!!
This applies to PZEV-certified cars currently registered in the following 9 states: California, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Rhode Island or Vermont.
You can determine if you have a PZEV car by the emissions label located under the hood. However, to absolutely confirm that your faulty TCM will be covered for FREE under the PZEV warranty, it is best to call the Mazda Customer Experience Center at 800-222-5500. They will ask for your VIN and confirm that your TCM is covered. Best to give them the TCM part # for a quicker response. The part # for all 2007-2009 Mazda 3s is L34T-18-9E1A (the last letter is the Revision and can be an A, B, C, D, or E.
A Mazda warranty repair will require you to go to the Mazda dealer for the diagnosis and repair. You will have to pay for the initial diagnosis fee, but it will be waived if the TCM is determined to be faulty.
So, if you have a PZEV-certified Mazda and you have determined that your TCM is faulty and you are in 1 of the 9 states noted above, you might want to have Mazda replace it for FREE vs. you buying a new one for $500+.
Note the PZEV 15-yr/150k mile warranty applies to most all emission-related parts so be sure and check before spending your own $$ and DIY'ing any of these related parts.
December-30th-2017, 07:56 PM
#52
Registered User
Join Date: Dec 2017
Posts: 2
Did you find out where your TCM is? I can't find mine in the location described on top of the transmission under the battery. Cheers
December-30th-2017, 07:58 PM
#53
Registered User
Join Date: Dec 2017
Posts: 2
January-12th-2018, 06:42 PM
#54
Registered User
Join Date: Jan 2018
Posts: 3
2010 MAZDA 3 AT/engine lights---wont shift past 3rd gear
2010 MAZDA 3........SAME PROBLEM AT/ENGINE LIGHT WONT SHIFT HIGHER THN 3RD GEAR , MY MECHANIC REPLACED SOLENOID "A" & SOLENOID "A" PRESSURE FLIUDS AND FILTER FOR $1200 STILL NOT FIXED.... IT WAS THE TRANSMISSION CONTROL MODULE...NEW$650....I GOT A REMANUFACTURED ON EBAY FROM MODULE REPAIR PRO FOR $250 IT WORKED FOR 2.5 WEEKS AND CAME BACK ON TODAY....IT HAS A ONE YEAR WARRANTY,I CALLED THEM THEY TOLD ME CHECK A COUPLE OF THINGS.....I CAN RETURN IT AND THEY WILL FIX OR REPLACE IT NO CHARGE....HAVE TO CHECK THE WIRING HARNESS TOMORROW....if no change shipping it back
January-12th-2018, 06:56 PM
#56
Registered User
Join Date: Jan 2018
Posts: 3
this is all good and accurate info from mazguy !
I replaced the tcm on my 2008 with 198k kms on the odometer - after checking various mazda forums on the internet.
My friendly kanata mazda dealer wanted $5,200 cndn. To replace the automatic transmission ? Huh? Wtf?
On top of that, it cost #129.95 for the diagnostic check which listed the cel codes.
My problem was eliminated with the purchase of a new l34t189e1e tcm for $550 cndn. (...from a different mazda dealer), and two hours of my time.
This is obviously a long term reliability problem that has plagued various years and models of mazda with automatic transmissions.
Mazda should do the right thing, step up and issue a tsb to cover this huge long term reliability problem, instead of gouging loyal customers with expensive replacement parts,
and allowing service techs to mis-diagnose simple transmission problems !
For this reason alone, i will never own another mazda product !
I replaced the tcm on my 2008 with 198k kms on the odometer - after checking various mazda forums on the internet.
My friendly kanata mazda dealer wanted $5,200 cndn. To replace the automatic transmission ? Huh? Wtf?
On top of that, it cost #129.95 for the diagnostic check which listed the cel codes.
My problem was eliminated with the purchase of a new l34t189e1e tcm for $550 cndn. (...from a different mazda dealer), and two hours of my time.
This is obviously a long term reliability problem that has plagued various years and models of mazda with automatic transmissions.
Mazda should do the right thing, step up and issue a tsb to cover this huge long term reliability problem, instead of gouging loyal customers with expensive replacement parts,
and allowing service techs to mis-diagnose simple transmission problems !
For this reason alone, i will never own another mazda product !
February-7th-2018, 11:25 AM
#57
Registered User
Join Date: Feb 2018
Posts: 1
TCM from www.promazdaparts.com
Has anyone in this forum used www.promazdaparts.com and how was your experience with them?
August-17th-2018, 10:27 AM
#58
Registered User
Join Date: May 2017
Posts: 4
Tcm
Has anyone in this forum used www.promazdaparts.com and how was your experience with them?
Must have an overstock of these units that were not selling at the rather expensive inflated price ?
November-4th-2019, 12:45 PM
#59
Registered User
Join Date: Nov 2019
Posts: 1
Just had mine replaced in PA at 84,655 miles under warranty - only had to pay for the diagnostic report
Hey guys, just some extra info that many of you may not be aware of concerning the infamous TCM (Transmission Control Module) failures.
If you have a Mazda 3 that is PZEV (Partial Zero Emission Vehicle) certified, then the TCM is a FREE warranty replaced item under the PZEV warranty for 15 years / 150,000 miles!!
This applies to PZEV-certified cars currently registered in the following 9 states: California, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Rhode Island or Vermont.
You can determine if you have a PZEV car by the emissions label located under the hood. However, to absolutely confirm that your faulty TCM will be covered for FREE under the PZEV warranty, it is best to call the Mazda Customer Experience Center at 800-222-5500. They will ask for your VIN and confirm that your TCM is covered. Best to give them the TCM part # for a quicker response. The part # for all 2007-2009 Mazda 3s is L34T-18-9E1A (the last letter is the Revision and can be an A, B, C, D, or E.
A Mazda warranty repair will require you to go to the Mazda dealer for the diagnosis and repair. You will have to pay for the initial diagnosis fee, but it will be waived if the TCM is determined to be faulty.
So, if you have a PZEV-certified Mazda and you have determined that your TCM is faulty and you are in 1 of the 9 states noted above, you might want to have Mazda replace it for FREE vs. you buying a new one for $500+.
Note the PZEV 15-yr/150k mile warranty applies to most all emission-related parts so be sure and check before spending your own $$ and DIY'ing any of these related parts.
If you have a Mazda 3 that is PZEV (Partial Zero Emission Vehicle) certified, then the TCM is a FREE warranty replaced item under the PZEV warranty for 15 years / 150,000 miles!!
This applies to PZEV-certified cars currently registered in the following 9 states: California, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Rhode Island or Vermont.
You can determine if you have a PZEV car by the emissions label located under the hood. However, to absolutely confirm that your faulty TCM will be covered for FREE under the PZEV warranty, it is best to call the Mazda Customer Experience Center at 800-222-5500. They will ask for your VIN and confirm that your TCM is covered. Best to give them the TCM part # for a quicker response. The part # for all 2007-2009 Mazda 3s is L34T-18-9E1A (the last letter is the Revision and can be an A, B, C, D, or E.
A Mazda warranty repair will require you to go to the Mazda dealer for the diagnosis and repair. You will have to pay for the initial diagnosis fee, but it will be waived if the TCM is determined to be faulty.
So, if you have a PZEV-certified Mazda and you have determined that your TCM is faulty and you are in 1 of the 9 states noted above, you might want to have Mazda replace it for FREE vs. you buying a new one for $500+.
Note the PZEV 15-yr/150k mile warranty applies to most all emission-related parts so be sure and check before spending your own $$ and DIY'ing any of these related parts.
November-6th-2019, 11:04 AM
#60
Registered User
Join Date: Nov 2019
Posts: 1
I want to say thanks to you and others on the forum on the diagnosis concerning the TCM. I was having the same problem (flashing AT light about every 5 minutes on a trip, random shifting even when in manual mode in my automatic transmission. In most cases, it suddenly shifted from 5th into 4th gear, but sometimes from 5th into 3rd with a jolt -- not fun at 65mph. Also, it sometimes shifted from 4th into 5th for no reason) with my 2012 Mazda5 with 59,000 miles, and it took me three places before resolution with the TCM. The first transmission place thought it might be the battery connection, and that was connected/reconnected and a flush and fill of tranny fluid for good measure. They did not find any codes. That didn't do anything.
Took it to the dealer, and they did not get any codes, but they were able to get the problem to happen to them while driving around. They adjusted the transmission fluid which was high, and they said it will be $4,961 for a new transmission, since it is probably a mechanical issue. We can get you in the next day for a new tranny. (Um, no. I don't think so. The AT light also sometimes comes on when the car is at a complete stop.)
Took it to a different transmission place that had better google reviews. They first tried a new speed sensor, but that didn't do anything. No charge. Took it back to them after buying a new Mazda L5E4-18-9E1E Auto Trans Control Unit for the Mazda 5. They replaced it NO CHARGE since they could not guarantee 100% that that would fix the problem. I am going to give them an awesome review and continue going to them for trans needs in the future. (BTW, I also gave them 2 dozen donuts in the couple of times we took it there.)
We have had it 1.5 days without a flashing AT light and no jolting downshifts. I am assuming the problem is fixed. Thanks guys and gals.
Joe
Took it to the dealer, and they did not get any codes, but they were able to get the problem to happen to them while driving around. They adjusted the transmission fluid which was high, and they said it will be $4,961 for a new transmission, since it is probably a mechanical issue. We can get you in the next day for a new tranny. (Um, no. I don't think so. The AT light also sometimes comes on when the car is at a complete stop.)
Took it to a different transmission place that had better google reviews. They first tried a new speed sensor, but that didn't do anything. No charge. Took it back to them after buying a new Mazda L5E4-18-9E1E Auto Trans Control Unit for the Mazda 5. They replaced it NO CHARGE since they could not guarantee 100% that that would fix the problem. I am going to give them an awesome review and continue going to them for trans needs in the future. (BTW, I also gave them 2 dozen donuts in the couple of times we took it there.)
We have had it 1.5 days without a flashing AT light and no jolting downshifts. I am assuming the problem is fixed. Thanks guys and gals.
Joe