D21 Hardbody 2WD L4-2389cc 2.4L SOHC MFI (KA24E) (1990)
Radio/Stereo: All Technical Service Bulletins
Audio - Diagnosis of Error Code SC-1
Classification:
EL92-012
Section:
Electrical
Reference:
TECHNICAL BULLETIN NTB 92-097
Models:
See Below
Date:
November 5, 1992
DIAGNOSIS OF AUDIO PROBLEMS: "SC-1" DISPLAYED ON THE HEAD UNIT
APPLIED MODELS:
All 1990-93 with Audio Head Units having "SC-1" feature
SERVICE INFORMATION:
The "SC-1" display, on head units, indicates a short circuit located in the speaker assembly(ies) or in the wiring/harness/connector assembly from the
head unit to the speaker. This is a protection circuit for the head unit. It is important to remember that there is usually no fault with the combo head unit.
The "SC-1" display usually indicates a defective speaker or pinched wire in the harness leading to the speakers or door jam connections.
TROUBLESHOOTING:
1.
After removing the head unit from the dash, disconnect the speaker harness connector and main harness from the head unit. With the ignition key
turned to the "on" position, measure the voltage between each of the speaker output wires and the vehicle chassis ground under the following
conditions:
^
Headlights turned on and off.
^
Wiper and washer switch cycled on and off.
^
Turn signals and hazard light cycled on and off.
^
Rear window defogger cycled on and off.
^
Doors opened and shut.
^
Brake light activated.
The voltage should be "zero". If voltage is measured, then, a problem exists within the related condition tested. Speaker connections to ground should
also be verified for continuity.
2.
Measure the resistance value - between the signal ground line and signal power line - of each speaker. The value should be 3 - 10 ohms. If the
value is below 1 ohm, the speaker has a problem.
WARRANTY INFORMATION:
Operation
OpCode
PNC
CS
CT FRT
Repair Wiring Harness
RA16AA
(*)
4Q
39
S/T