Three-digit EEC codes

Model years 1989 to 1991 used 2-digit codes. 1992-1995 use 3-digit codes. 1996-1999 use 5-digit codes (OBD-II).

Code	KOEO	KOER	Continuous	Check Engine	Description
111					Systems pass.
112					Air charge temperature (ACT) sensor indicated 254degF. Circuit grounded.
113					ACT indicated -40degF. Circuit open.
114					ACT out of self-test range.
115					Engine coolant temperature (ECT) sensor out of self-test range.
117					ECT indicated 254degF. Circuit grounded.
118					ECT indicated -40degF. Circuit open.
121					Throttle position (TP) sensor out of self-test range.
122					TP sensor circuit below minimum voltage.
123					TP sensor circuit above maximum voltage.
124					TP circuit output higher than expected.
125					TP circuit output lower than expected.
126					CID circuit failure.
129					Insufficient mass air flow (MAF) change during dynamic response test.
136					HEGO sensor indicates system lean (LH).
137					HEGO sensor indicates system rich (LH).
139					No HEGO switching detected (LH).
144					No HEGO switching detected (RH).
157					MAF circuit below minimum voltage.
158					MAF circuit above maximum voltage.
159					MAF out of self-test range.
167					Insufficient throttle position change during dynamic response test.
171					No HEGO switching detected / adaptive fuel at limit (RH).
172					HEGO sensor indicates system lean (RH).
173					HEGO sensor indicates system rich (RH).
174					HEGO switching time is slow (RH).
175					No HEGO switching detected / adaptive fuel at limit (LH).
176					HEGO sensor indicates system lean (LH).
177					HEGO sensor indicates system rich (LH).
178					HEGO switching time is slow (LH).
179					Adaptive fuel lean limit is reached (RH).
181					Adaptive fuel rich limit is reached (RH).
182					Adaptive fuel lean limit is reached at idle (RH).
183					Adaptive fuel rich limit is reached at idle (RH).
184					MAF higher than expected
185					MAF lower than expected
186					Injector pulse width higher than expected.
187					Injector pulse width lower than expected.
188					Adaptive fuel lean limit is reached (LH).
189					Adaptive fuel rich limit is reached (LH).
191					Adaptive fuel lean limit is reached at idle (LH).
192					Adaptive fuel rich limit is reached at idle (LH).
211					PIP circuit fault.
212					IDM circuit failure / SPOUT circuit grounded.
213					SPOUT circuit open.
214					CID circuit failure.
215					Coil 1 primary circuit failure.
216					Coil 2 primary circuit failure.
217					Coil 3 primary circuit failure.
219					SPOUT signal defaulted to 10 degrees BTDC / SPOUT circuit open.
225					Knock sensor (KS) not sensed during dynamic response test.
326					DPFE circuit voltage lower than expected.
327					DPFE output circuit below minimum voltage.
332					EGR valve opening not detected.
335					DPFE sensor voltage higher or lower than expected.
336					Exhaust backpressure high / PFE circuit voltage high.
337					DPFE output circuit above maximum voltage.
411					Cannot control RPM during self-test low RPM check.
412					Cannot control RPM during self-test high RPM check.
452					Insufficient input from vehicle speed sensor (VSS).
511					EEC processor ROM test failure.
512					EEC processor RAM test failure.
513					Failure in EEC processor internal voltage.
519					PSPS circuit open.
521					PSPS circuit did not change states.
522					Indicates vehicle in gear.
524					Low speed fuel pump circuit open (battery to ECA).
526					NPS circuit closed; air conditioning on.
536					BOO circuit failure.
538					Operator error (dynamic response / cylinder balance tests).
539					Air conditioning on / defrost on during KOEO.
542					Fuel pump secondary circuit failure.
543					Fuel pump secondary circuit failure.
551					IAS circuit failure.
556					Fuel pump primary circuit failure.
557					Low speed primary fuel pump circuit failure.
558					EVR circuit failure.
564					EDF circuit failure.
565					CANP solenoid circuit failure.
565					Hard fault present (FMEM mode).