Volvo960 Codigos

G - TESTS W/CODES
1994 Volvo 960

1994 ENGINE PERFORMANCE
Volvo Self-Diagnostics
960

INTRODUCTION
If no faults were found while performing BASIC DIAGNOSTIC
PROCEDURES, proceed with SELF-DIAGNOSTIC SYSTEM. If no fault codes or
only pass codes are present, proceed to H - TESTS W/O CODES article in
the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH
IDLE, NO START,etc.).
NOTE:

All voltage tests should be performed using a Digital
Volt-Ohmmeter (DVOM) with a minimum 10-megohm input
impedance, unless specifically stated otherwise in testing
procedures.

SELF-DIAGNOSTIC SYSTEM
960 uses a Motronic 1.8 diagnostic system, which uses a
single Electronic Control Unit (ECU) to control fuel injection and
ignition systems. In addition, Motronic 1.8 diagnosticsystem
determines whether A/C compressor may be switched on, reduces engine
torque in response to a signal from automatic transmission, and
controls radiator fan.
Diagnostic unit for retrieving codes is located in engine
compartment, in front of left strut assembly. Diagnostic unit is
equipped with an LED indicator, activation button and function select
cable. See Fig. 1.
Diagnostic unitoutput socket No. 2 is used to retrieve all
codes. Once selector cable has been inserted in correct slot,
depressing button once, twice or 3 times selects from one of 3 control
(fault tracing) functions. Faults stored in ECU memory are read by
observing LED flashes. Diagnostic system stores 18 fault codes.
All fault codes contain 3 digits (example: 4-1-3). Since
codes have 3 digits, each coderequires 3 series of flashes. A 3second interval separates series of flashes. See Fig. 2.

Fig. 1: Identifying Diagnostic Unit
Courtesy of Volvo Cars of North America.

Fig. 2: Counting Red LED Code Flashes For Code 2-1-3
Courtesy of Volvo Cars of North America.

RETRIEVING CODES
CAUTION: Never disconnect or connect ECU connector with ignition
switch in ON position. Ensure ignition isoff and fuse No.
24 is removed.
ECU is equipped with diagnostic functions in form of selfdiagnostics (Test Mode No. 1), function testing (Test Mode No. 2) and
control testing (Test Mode No. 3). Access to diagnostic system is
provided by socket No. 2 on diagnostic unit with ignition on.
Test Mode No. 1 (Retrieving Codes)
1) ECU can record 18 fault codes. Fault codes stored in
memory can bedisplayed by pressing test button "A" on diagnostic unit
for an instant. Control unit memory can retain codes from 10 minutes
to 24 hours after interruption of electrical supply.
2) Control unit will begin to use a faulty or missing signal
immediately after it has been corrected rather than remaining in limphome mode. Fault code, however, will remain in memory.
3) To retrieve codes, opendiagnostic unit cover and connect
test lead to socket No. 2. Turn ignition on. Enter test mode No. 1 by
pressing test button once for 1-3 seconds.
4) Observe LED, and count number of flashes in 3 digit series
comprising a fault code. Because series are displayed at 3-second
intervals, codes can be easily distinguished.
5) If a fault code is retrieved, refer to FAULT CODES table
under FAULT CODEDEFINITION. Depress push button again, and check for
additional codes. Depress push button a third time if necessary. If
first code repeats, no other codes are present. Control unit can store
all 18 codes simultaneously.
Test Mode No. 2
This function is activated by briefly pressing test button
"A" 2 times, causing LED to rapidly flash. Control unit will flash a
code indicating receipt ofa signal from following components:
*
*
*
*
*
*

3-3-2 - Throttle switch (throttle moved from idle).
3-3-3 - Throttle switch (throttle moved from WOT).
1-2-4 - Starter inhibitor switch, when gear selector is moved
from a drive position to N or P.
1-4-1 - Timing pick-up, when starter motor is running.
1-1-4 - ECC control panel, when A/C button is depressed or
released.
1-3-4 -...