ECM DTC EO74: Mat Signal Interrupt: Action

Code set, No Service telltale

• This code sets when the MAT temperature changes 7 degrees in .25 seconds.
• This code will not turn on the "Service Engine Soon" indicator.
• This code can be caused by an open, short to ground or short to voltage in CKT 472 and/or 469; an open or short in the sensor connector, engine to dash connector, or ECM connector. A defective sensor can also cause the code.
• This code will never set current, since it is set by a MAT sensor value which changes faster than what can occur in a normally operating system.
• This code indicates an intermittent signal fault which could cause a driveability symptom.

When all diagnosis and repairs are completed, clear codes and verify proper operation.