Code 1-1-2 & Code 1-2-2

Code 1-1-2 is stored if a safety feature has been tripped, or an abnormal speed signal. Code is stored only if control unit has had a normal signal at some time during road test and not for stationary interruptions. Code 1-2-2 is stored when ignition is turned on. It remains until vehicle speed has been greater than 22 MPH for at least 15 seconds. If code remains after a road test at speeds greater than 22 MPH, control unit is not getting a speed signal.
If speedometer is not operating correctly, fault is not with control unit. If speedometer does operate correctly, there is a proper input signal to instrument cluster. Go to next step and check if code for 12-pulse output signal is registered with instrument cluster, fuel and ignition systems.
Enter diagnostic test mode No. 1 for instrument cluster by placing selector cable in socket No. 7 of diagnostic unit "A". Check for codes. Check for fuel system codes by placing selector cable in socket No. 2 of diagnostic unit "A". Check for ignition system codes by placing selector cable in socket No. 6 of diagnostic unit "A".
If Code 1-3-1 for instrument cluster, Code 3-1-1 for fuel system, and Code 3-1-1 for ignition system are set, connection between instrument cluster and cruise control, fuel system, and ignition system is shorted to ground or voltage. Remove cruise control unit from underhood relay/fuse block.
Raise and support front of vehicle. Turn ignition on. Connect voltmeter between cruise control unit base terminal 8S and ground. Turn front wheels. If voltmeter fluctuates between 0 and 12 volts, replace control module. If voltmeter constantly indicates high (12 volts) or low (zero volts), check wiring between cruise control unit and instrument cluster.