WTF happened!?

The situation:
So my EVO gave me the finger, last night I had the car up on the lift checking over my suspension looking for some rattles. Checked the torque on some bolts, adjusted somethings, pushed and pulled, but never touched anything other than the suspension. Took the car out to see if anything made a difference. I didn't get 2 blocks from the house and the "ASC service require" message came on, the idle started to surge from 500-1500 and my speed was limited to 20mph. I limped the car back into the garage and pulled the laptop in to read codes C121C, C1219, U0100, U1417, no P codes.

The remedy:
After reading the description of the codes and a lot of them pointed to broken CANBUS wires or an ECU failure. Being reasonably sure that the wires had not been broken or stretched I reflashed my ECU with the same .bin (OE for the car). NO change. So I reflashed the ECU again with 80304 Tephra MOD v3/RAX v3 and the car drove fine, no issue. NO changes have been made to the 80304 bin other than to allow for the TephraMOD v3 edit and RAX patch v3 edit.

PMH (past mod history):
2015 Evo X FE w/ 17k miles, ECU Flash (not tuned), turbo-back exhaust, Short ram intake, 1-piece UICP, F/R sway bars w/ adjustable end-links, complete Radium fuel system, shifter, Evo 9 CMC, twin disk push-type clutch, trans mounts, track brake pads and boost/AFR gauge. Aside from the clutch and ECU flash nothing too crazy. Redoing the fuel system and CMC was pretty invasive but nothing outlandish or requiring a lot of modification to get to work. Prepping for a larger turbo (GTX3071R gen2)

Issues/manfunctions:
After reflashing the ECU with the TephraMOD the CEL would start flashing while under prolonged periods of acceleration, for example, a 3 gear pull while on the highway or the NASCAR straightaway at Gateway Raceway. The ECU would intermittently have P0200 (not injector specific malfunction) & P1960 (no description) but no misfire code. Neither of these codes is specific to the Evo X. The car never felt like it was misfiring and none of the data logs showed a lean condition. Not being able to find a source of the malfunction and "ever since" I flashed the ECU this problem began, I reflashed the ECU with the OE .bin file. The CEL quite coming on with the previously described condition and that was a month ago.

DTC C121C: Torque request signal rejection
DTC SET CONDITIONS
This diagnostic trouble code is set when the output decrease request is rejected by the engine control module.
PROBABLE CAUSES

• Wrong coding
• Engine ECU malfunction
• ASC-ECU malfunction
• External noise interference

DTC C1219: Abnormality in steering wheel speed signal
DTC SET CONDITIONS
This diagnostic trouble code is set if any malfunction below is found:

• The tolerance of the neutral position of steering wheel sensor exceeds the specified range.
• Abnormality in steering wheel sensor output value
• Abnormality is detected by a comparison of output value from the steering wheel sensor with the output values from wheel speed sensor and G and yaw rate sensor.

PROBABLE CAUSES

• Improper installation of steering wheel sensor
• Wheel alignment not performed
• Steering wheel sensor malfunction
• Different steering wheel
• G and yaw rate sensor malfunction
• Wheel speed sensor malfunction
• ASC-ECU malfunction
• External noise interference

DTC U0100: Engine time-out error
DTC SET CONDITIONS
The diagnostic trouble code is stored if ASC-ECU cannot receive the signal sent from other ECU for a specified period.
PROBABLE CAUSES

• Wiring harness or connector failure of CAN bus line
• Engine ECU malfunction
• ASC-ECU malfunction
• Connector disconnected or improperly connected
• Stretched or broken wires

DTC U1417: Variant coding value invalid (includes faulty installation)
DTC SET CONDITIONS
ASC-ECU communicates with ETACS-ECU via CAN bus lines. This diagnostic trouble code is set when the vehicle information received from ETACS-ECU is invalid. This diagnostic trouble code is also set when the engine control module sends the ASC intervention rejection (ASC not supported) signal consecutively.
PROBABLE CAUSES

• ETACS-ECU malfunction
• ECM malfunction
• ETACS-ECUs have been interchanged between two vehicles.
• ASC-ECU malfunction
• Noise interference
• ASC-ECUs have been interchanged between two vehicles

 

When you state ECU Flash (not tuned) what do you mean? You have a untouched factory ROM on there with all those mods?

If so, you can easily trip the factory airflow limit maps with those mods. That is why when you flash the Tephra ROM (that has those turned off), you have no issues.

Your CEL is flashing with the TephraMOD because you are getting knock, which is not surprising if you are going WOT with all those mods on a stock rom. Stop doing that.

 

"When you state ECU Flash (not tuned) what do you mean?"
The ROM file is unaltered with the exception of the TephraMOD and RAX patch.

"You have a untouched factory ROM on there with all those mods?"
Yes... The only mods that have been done that add any power is the turbo-back exhaust, short ram intake and to a small extent the 1-piece UICP.

"If so, you can easily trip the factory airflow limit maps with those mods. That is why when you flash the Tephra ROM (that has those turned off), you have no issues."
Honestly, I have no clue, but I'll look in to turning off the airflow limits. The only reason I've messing about with the tuning aspect of the car is so that everything setup ready to go and I can trouble shoot some basic issues if any were to a raise when I have the car remote tuned on a dyno. Having to tow the car out to the shop, paying by the hour for the dyno time plus the cost of the tune adds up quick. Anything I can do or learn to mid agate the issues that will pop-up will pay dividends later.

 

Happy to set you up with a proper base rom for your needs if you want. Just send me your current ROM.

 

WOW! Thanks. Would it help if I data logged some 3rd gear pulls?

 

Send me a PM