Throwing Codes

The purpose of this entry which also doubles as a semi update on my build thread is to help you determine why your sr20det doesn’t run right. The most logical thing you can do is run an ecu diagnostic with consult if you have that available to you.

But the good old fashion non fancy way is Morse code.

You can accomplish this task of pulling a code from your ecu by setting it into diagnostic mode by turning the adjustment screw on the back completely clockwise until it stops, then counter clockwise to the other stop (do not force it past where it stops, you don’t need tree chopping strength for this.) Here is a video demonstrating my results.





Pretty simple right, so lets review what happens.

Once you’re in diagnostic mode the ECU light/CEL Light (depending on your model) will flash a series of blips, to best describe this I will just quote the ECU Fault Codes info from 240sxmotoring.com, normally I would link you there. But in my travels for knowledge concerning these cars, if they go out of business or are bought out, etc.

This information is lost in limbo. So best to spread it in my opinion. Anyway the code’s and how to read them as follows.

Long Flash - 0.6 seconds on (the first digit)

Short Flash - 0.3 seconds on (the second digit)

Long Gap - 2.1 seconds off (used between codes)

Short Gap - 0.9 seconds off (used between digits)

There are two digits in each code. Count the long flashes, then the short flashes (only count how many times the light is ON) and you’ll have a 2 digit code. These codes are covered in the service manual.

Code Meaning

11 - Camshaft Position Sensor

12 - Air Flow Meter

13 - Coolant Temperature Sensor

14 - Vehicle Speed Sensor

21 - Ignition Signal

25 - IACV - AAC Valve

26 - Boost Pressure Sensor

31 - ECM Fault

32 - Exhaust Gas Recirculation System

33 - Front EGO Sensor (O2-1 Sensor)

34 - Knock Sensor

35 - EGR Temperature Sensor

36 - EGR BPT Valve

37 - Closed Loop System

41 - Intake Air Temperature Sensor

43 - Throttle Position Sensor

54 - Signal from Auto Transmission

55 - Other Malfunction. CONSULT Terminal Required

63 - Cylinder 6 Misfire (?)

64 - Cylinder 5 Misfire (?)

65 - Cylinder 4 Misfire

66 - Cylinder 3 Misfire

67 - Cylinder 2 Misfire

68 - Cylinder 1 Misfire

71 - Random Misfire

72 - TW Catalyst System

76 - Fuel Injection System

77 - Rear EGO Sensor (O2-2)

82 - Crank Position Sensor

84 - Automatic Transmission Diagnostic Comms Line

95 - Crank Position Cog

98 - Coolant Temperature Sensor

103 - Park/Neutral Switch

105 - EGR Solenoid

111 - Inhibitor Switch

112 - Automatic Transmission Speed Sensor

113 - Automatic Transmission 1st Signal

114 - Automatic Transmission 2nd Signal

115 - Automatic Transmission 3rd Signal

116 - Automatic Transmission 4th Signal

118 - Automatic Transmission Shift Solenoid Valve A

121 - Automatic Transmission Shift Solenoid Valve B

123 - Automatic Transmission Overrun Clutch Solenoid Valve

124 - Automatic Transmission TOR Conv Solenoid Valve

125 - Automatic Transmission Line Pressure Solenoid

126 - Automatic Transmission Throttle Position Sensor

127 - Automatic Transmission Engine Speed Signal

128 - Automatic Transmission Fluid Temperature Sensor

So with that information I am throwing codes: 12 - Mass Air Flow Sensor, 13 - Coolant Temp Sensor, and 34 - Knock Sensor.

In my next update touching upon this subject, I will document basically how I am going to tackle these items.

12, and 13, both seem like bad sensors or just bad wiring on my part.

34 - knock sensor and I have like a bad history, every motor I have owned even back to my Honda roots have been plagued by the godamned knock sensor, let alone I hate these things will all of my heart and being. It’s the most USELESS thing ever on your motor, for instance I have solid polyurethane motor mounts on this engine, which cause a SHITLOAD of vibration, which obviously the knock sensor can possibly confuse with engine knock.

And then puts your car in limp mode, and so I am just going to eliminate the knock sensor and put an ohm resistor in it’s place and call it a day. Don’t consider my experience to be the end all sermon, if this thing wasn’t 100 dollars to replace, and something you’re guaranteed to reap the benefits of changing to get your car running ship shape. I would document how to change your knock sensor, and all would be great…

But seriously in my experience, I spent 124 dollars on a BRAND NEW knock sensor, put it on the motor, torqued it to spec, and bam.

Code 34, all of the wiring checked out. All voltages were showing the knock sensor was working properly, it just decided my engine was knocking. Which it isn’t, stock boost, stock turbo. And quite frankly I am going to get this car on the road in 2009, the fuck if it will spend another year or month in my garage.

I’ll make sure to keep you kids posted.

Editors note: If you want to try troubleshooting these codes yourself then congratulations, you have earned my respect. To help you along if you have downloaded the sr20det FSM from various places on the net (has a yellow jun 240sx as it’s front page) if you head on to PDF page 179 it will list where in the EC section of the manual you will find the troubleshooting steps for the codes you pulled.

For instance.

ECU Code 12 = Diagnosis Procedure 24 which is located in EC113 (PDF PAGES 249-251)
ECU Code 13 = Diagnosis Procedure 25 which is located in EC116 (PDF PAGES 252-255)
ECU Code 34 = Diagnosis Procedure 28 which is located in EC132 (PDF PAGES 268-270)

Also Just an FYI that FSM is for an S14 Sr20det, the wiring is essentially the same, but the ECU pinouts I assure you are different for other sr20det models. In my case, an s13 redtop. Keep that in mind when tracing wires…

W.E.

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