Diagnostic Procedure 19 — Surge

CHECK EXHAUST GAS SENSOR. 1. See "M/R F/C MNT" in "DATA MONITOR" mode. 2. Maintaining engine at 2,000 rpm under no-load (with engine warmed up sufficiently.), check to make sure that the monitor fluctuates between "LEAN" and "RICH" more than 5 times during 10 seconds. RICH -> LEAN -> RICH -> (1 time, 2 times) LEAN -> RICH ....... — OR — 1. Set "Exhaust gas sensor monitor" in the self-diagnostic Mode II. (See page EF & EC-412.) 2. Maintaining engine at 2,000 rpm under no load, check that the RED L.E.D. on the E.C.U. or the check engine light on the instrument panel goes ON and OFF more than 5 times during 10 seconds.

TRY A KNOWN GOOD E.C.U.*

Replace E.C.U.