405 L4-1905cc 1.9L (1989)
Engine Control Unit: Customer Interest
A/C - Engine Stalls at Idle, Hesitation, MIL Flashes
BULLETIN NO. 384
MOTRONIC ECU REPLACEMENT
ALL 1989 MODEL YEAR 405 VEHICLES
Late production Motronic ECUs are equipped with an A/C compressor cut-out feature during full-load acceleration. These ECUs may not be compatible
with 1989 model 405s without modification.
After replacing an ECU on a 1989 405:
Run the vehicle at idle and engage the A/C several times
If the vehicle stalls at idle or experiences a momentary hesitation accompanied by a flash of the "Check Engine" light when the A/C compressor cycles
while driving on the highway, perform the following modification:
Locate the A/C compressor cut-out relay in the diagnostic box on the right side of the engine compartment (black connector with wire numbers 6, 6A,
6C, 20B, and 23C).
If there is no relay in the connector, and a jumper is installed between terminals 3 and 4, no further modification is necessary.
If the relay is installed in the connector, locate wire number 23C in pin 2 of the connector; cut the wire from the terminal as close to the connector as
possible, and tape the wire back to the harness to insulate and secure it.
Start engine and activate A/C switch several times to ensure that the engine does not stumble or stall.
This repair will be accepted when performed within the New Vehicle Limited Warranty period of three (3) years and/or 36,000 miles, whichever occurs
Additional Time Allowance: