2000-2003 Honda TRX350 Rancher factory service manual, Page 340Get this manual
ELECTRIC SHIFT PROGRAM (ESP) Problem Code 1: ECU (writing and recording circuit) Delete the problem code numberCheck the ES system failure (the gear indicator blinks) when turning the ignition switch from OFF'' to ON''Blinks Replace the ECU with new one and troubleshoot again
No blinks No problem (temporary failure)
Problem Code 2: ES Shift Switch System (Up And Down)
Check the connections of the ECU, gear shift switch and related circuitAbnormal Loose or poor connections in related circuit
Disconnect the ECU connector (22PBrown)Check for continuity at the wire harness side connector while pushing the shift switches up or down
Abnormal
Check for mud or water in the left handlebar switch housing
Abnormal
Clean the left handlebar switch housing