Here is how to check the codes on a FC3S S4 1986-88.

-Diagnostic connector

The diagnostic connector can be found on the front-left side of the vehicle, between the battery and the front-left-pillar. It is a green female, with 6 slots, where only 4 are used. See photo below:


The 4 entry slots are:

Signal Name Colours Source Notes
DCC1 Digital Code Checker 1 Yellow/Black ECU pin 1A open collector
DCC2 Digital Code Checker 2 Yellow/Red ECU pin 1B open collector
GL Green Lamp Yellow ECU pin 1D open collector
ABR Air Bypass Relay Black/White ABR +12V Input


Their positions are:

What to read the codes with:
The codes can be read with an analogue voltmeter but this guide covers a much simpler method. Using an LED (light emitting diode), a resistor (if needed) and a little wiring. All available for under $5 at most electronic shops (such as Addison/Maddison in Qc) and will give you a reading in less than 5 minutes.

To make your tester, you’ll need:
-Two (2) 12V LED lights de 12V or other with a resistance for 12V (the shop should be abe to advise you of what you need if they don’t have a 12V LED)
-Three (3) male connectors (preferably insulated)
-2 feet red and yellow wiring. (IF the LEDs don’t come with wiring)

Assemble as pictured in the graphic:

It should look like this:

Number the LED with the corresponding connectors, it makes things easier.

Read the codes:
-Put the key to ”Off”.
-Connect the tester, LED 1 in DCC1, LED 2 in DCC2 and the double-wire in ABR.

-Turn the key to “Accesory”, the LED should light up for +/- 3 seconds.
-If there is an error, one or both lights should flash the code.

Here’s how to interpret the codes:
-The DCC1 indicates the units and the DCC2 indicates dozens.
-One flash (C) short (1/2 second) = 1
-One flash (L) long (1 second) = 5
-A pause (P) of 2 seconds between flashes indicates the end of a code.

-Add it all up, and you have your code!
(Example: DCC1 flash 1 time L and 3 times C, this gives 08 and DCC2 does not flash, that gives 00, so the code is 08.
Other example: DCC1 flash 2 times C, this gives 02 and DCC2 flash 1 time C, this gives 10, so the code is 12.)

List of codes:
Code 01 – Crank angle sensor
DCC1: C P… (1 C… long pause… repeat)
DCC2: Does NOT light.

Code 02 – Air flow meter
DCC1: CC P… (2 C… long pause… repeat)
DCC2: Does NOT light.

Code 03 – Water thermo sensor
DCC1: CCC P… (3 C… long pause… repeat)
DCC2: Does NOT light.

Code 04 – Intake air temp sensor
DCC1: CCCC P… (4 C… long pause… repeat)
DCC2: Does NOT light

Code 05 – Oxygen (O2) sensor
DCC1: L P… (1 long… long pause… repeat)
DCC2: Does NOT light

Code 06 – Throttle sensor
DCC1: LC P… (1 long… 1 C… long pause… repeat)
DCC2: Does NOT light

Code 07 – Boost/Pressure sensor
DCC1: LCC P… (1 long… 2 C… long pause… repeat)
DCC2: Does NOT light.

Code 09 – Atmospheric Pressure sensor
DCC1: LCCCC P… (1 long… 4 C… long pause… repeat)
DCC2: Does NOT light.

Code 12 – Trailing side coil failure
DCC1: CC P… (2 C… long pause… repeat)
DCC2: C P… (1 C… long pause… repeat)

Code 15 – Intake air temperature sensor
DCC1: L P… (1 long… long pause… repeat)
DCC2: C P… (1 C… long pause… repeat)


1. Open the « DIAGNOSIS » box situated under the hood. (near the battery)

2.  Make a “jumper” between the terminal TEN and the terminal GND. If you have an AMERICAN/CANADIAN, skip point 3.

3.a) Connect a 680 ohms resistance in the terminal B+

b) Replay an LED at the end of this resistance and connect to terminal FEN.

4.Put the key to ON.

5.American/Canadian: The “Check engine” light will flash a number of times

JDM: The LED light will flash a number of times.

You will notice both long and short flashes. One long flash = 10 and one short flash = 1.

(For exemple: Long-long-long-short-short = 32. 32 in the list = Solenoid valve – switching, which means you should check this module.)

1 Ignition coil (trailing side)
2 Crank position NE sensor
3 Crank position G sensor
5 Knock sensor
8 Airflow meter (AFM)
9 Water thermosensor
10 Intake air thermosensor (AFM)
11 Intake air thermosensor (engine)
12 Throttle sensor – full range
13 Pressure sensor – intake manifold
14 Atmospheric pressure sensor (built in ECU)
15 oxygen sensor
17 Feedback system for O2 sensor
18 Throttle sensor – narrow range
20 Metering oil pump position sensor
23 Fuel thermosensor
25 Solenoid valve – pressure regulator control
26 metering oil pump stepper motor
27 Metering oil pump
28 Solenoid valve – EGR
29 Solenoid valve – EGR vent
30 Solenoid valve – split air bypass
31 solenoid valve – relief 1
32 Solenoid valve – switching
33 Solenoid valve – port air bypass
34 Solenoid valve – idle speed control (BAC)
37 Metering oil pump
38 Solenoid valve – accelerated warmup system and air supply valve
39 Solenoid valve – relief 2
40 Solenoid valve – purge control (auxilary port valve)
41 Solenoid valve – variable dynamic effect intake (VDI)
42 Solenoid valve – turbo precontrol
43 Solenoid valve – wastegate control
44 Solenoid valve – turbo control
45 Solenoid valve – charge control
46 Solenoid valve – charge relief control
50 Solenoid valve – double throttle control
51 Fuel pump relay
54 Air pump relay
65 Air conditioning signal
71 Injector – front secondary
73 Injector – rear secondary
76 Slip lockup signal
77 Torque reduced signal

To reset the codes and restart to see if the problem was resolved, you simply need to disconnect the battery, apply the brakes for 5 seconds, and reconnect.