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Home >> Volvo >> 1993 >> 850 Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostic System >> Retrieving Codes >> Fuel Injection & Ignition Systems
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Fuel Injection & Ignition Systems

Each system features a self-diagnostic function for fault tracing. Codes are retrieved using diagnostic unit "A" located in engine compartment, in front of right strut tower. Diagnostic unit "A" is equipped with an LED indicator, activation button and function selector cable. See Fig 1 .

NOTE: Diagnostic unit "B" is not used for engine performance applications.
Fig 1: Identifying Diagnostic Unit "A"
G121540Courtesy of VOLVO CARS OF NORTH AMERICA.

Diagnostic unit "A" output socket No. 2 is used for fuel injection diagnosis, and socket No. 6 is used for ignition system diagnosis. Once function selector cable has been inserted in correct socket, depress button and keep depressed for more than one second (but not more than 3 seconds). Observe LED and count number of flashes to determine diagnostic trouble code, as faults stored in Electronic Control Unit (ECU) memory are read by observing LED flashes. If LED does not flash, see DIAGNOSTIC UNIT "A" LED DOES NOT FLASH.

Diagnostic system for fuel injection and ignition each store 13 codes. All codes contain 3 digits (example: 4-1-3). Since all codes have 3 digits, each code requires 3 series of flashes. A 3-second interval separates each series of flashes. See appropriate TROUBLE CODE DEFINITION table under TROUBLE CODE IDENTIFICATION  .