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Engine light comes on every day with same codes

Posted: Tue Jun 12, 2012 12:33 pm
by jdellis
I have a 2006 Mazda MX5 with one of the first Cosworth superchargers (engine was rebuilt by Cosworth for free). I have completely replaced the exhaust system with racing beat headers,mid-pipe, and Borla exhaust.

However, I every day within two miles the engine light comes on and I get several of the following codes, especially p2035. I have replaced the throttle pedal mechanism ,etc.

I understand this is a common problem in stock MX-5s and that Mazda must update the software. Does anyone have any ideas about how to fix my problem?

DTC Codes 2006 Mazda

May 12th
P0102 Throttle Position Sensor Circuit Malfunction
P2187 System too lean at Idle Bank
P2135 Electronic Throttle Control Throtttle Position Sensor A/B Voltage Correlation
P2187 System too lean at Idle Bank

May 14th
P2187 System too lean at Idle Bank

May 15th
P0102 Throttle Position Sensor Circuit Malfunction
P2187 System too lean at Idle Bank
P0102 Throttle Position Sensor Circuit Malfunction
P0421 Bank1 Warm Up Catalyst Efficiency Below Limit

Re: Engine light comes on every day with same codes

Posted: Tue Jun 12, 2012 2:52 pm
by Brian
Talk with Mike at MotoEast....because he did my tune on our 2007 Cosworth and we don't get any of these codes.

Re: Engine light comes on every day with same codes

Posted: Tue Jun 12, 2012 6:35 pm
by AZ Sun Lover
The P0421 is because of "No Cat" in the Racing Beat mid-pipe. Add one or two spacers to the rear 02 sensor. Maybe Thermal, PPE or Enthuzacar can add a cat to the mid-pipe. Best bet is to buy a new mid-pipe and sell the old one. Mid-pipes with no cats will not fetch much $. Ask for a ceramic cat in the mid-pipe. PPE & Jason @ Enthuza can make mid-pipes at any time. Jason now has a ceramic coater he uses for his V8 Miata exhaust systems. Might want to coat the SS Racing Beat header too, as it will keep the heat down in the engine bay.

All the best,
AZ

Re: Engine light comes on every day with same codes

Posted: Thu Jun 21, 2012 7:53 am
by jdellis
Now that it is above 90 degrees outside, the miata through a 2135 code and stuck at around 2000 RPMs. Push the pedal and no response. I have a scan tool and erased the codes. On one occasion, I had to stop in traffic and reset the codes 8 times in four blocks. During that time, after erasing the codes (two 2135), I restarted and it immediately suck at 2000 RPMS and through the 2135 code (four times in a row, before I could get the throttle to respond).

My mechanic checked with the head mechanic at the Mazda dealership and they indicated that several stock Miatas have had the same problem and that it is not a problem with the supercharger, exhaust system, or Oxygen sensors. The mechanic at Mazda dealership indicated that Mazda needs to update the software, but hasn't done so, because it isn't affecting enough vehicles.

Has any one else had a similar problem, with or without a supercharger?

Thanks for the advice so far.

Re: Engine light comes on every day with same codes

Posted: Thu Jun 21, 2012 8:02 am
by Brian
Never seen these issues here.