ECU Trouble Codes
By Danny Pham
How to Read the Trouble Codes from the ECU
- Locate the ECU (under your dash in the
center) and look for a small screw next to a LED (towards the back end).
- Turn the ignition to the ON position (engine
- Turn the screw fully clockwise, wait 2
seconds, and then turn it fully counter-clockwise.
The LED will start to display the code by a
series of long flashes, followed by a series of short flashes. Your check engine light on
the instrument cluster will also flash in the same sequence. This sequence will repeat.
to see the trouble codes for the 200SX SE-R
The following is from the Haynes manual for
91-94 Sentras (both 1.6 and 2.0).
|Flashes (long, short)
||Circuit or system
||Crank angle sensor/circuit
||Mass airflow sensor/circuit
||Coolant temp sensor
||Vehicle speed sensor
||ECM control unit
||Exhaust gas temp sensor
||TPS - Throttle position sensor
||(NORMAL SYSTEM OPERATION)
Resetting the ECU
Once the screw is turned fully clockwise
and counter-clockwise again, the ECU will be reset.