Hello everyone... I have this problem... my 89 240SX KA24 SOHC is not running well, I ran the diagnostic on th ECU a gave me a code 41 that is the Intake Air temperature sensor... but... there are no Intake Air temperature sensor... or I can't find it... it sopposed to be inside the box of the air cleaner... but, there are nothing... can anyone help me find this sensor... Thanks...
Modified by JP240SX at 10:12 AM 5/14/2007
ECU code 41...
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vancouverbc
- Posts: 3197
- Joined: Thu Oct 30, 2003 1:30 am
- Car: 1991 240sx
Re: ECU code 41... (JP240SX)
code 41 is for 95-98 240sx. your 89 does not have air temp sensor
How to read trouble code on your 240sx electronic control unit SOHC
******************************************************How to Read Malfunction Codes for Your SOHC 240SX=================================================On most car, only a jump wire or a screw driver is required to read the trouble code store on the engine computer. This the case for the 240 sx. The following intructions allow you to easily read and erase trouble code on your car electronic control unit (ECU)
The instructions come from the nissan 240sx 1989 12 valves engine service manual. There is a good chance that later models are similar.
In a few word, reading to code require accessing to the ECU, placing the unit in self diagnosis mode using a screw driver and looking at the flashing lamps on the unit to see what code is displayed.
1. Accessing to the ECU
The ECU is located to the right of the passenger footwell. You need to remove two fastener of the right doorstep in order to remove the kick panel. To remove the plastic fasteners, unscrew the center part and pull out the other part. Two metal screw and a fastener hold the kick panel. Some kind of pitch is also present.
Under the panel you now see the ECU with its connector. Unfortunaly, you have to access to the other side of the ECU. Unscrew the unit and turn it 180 degree on the vertical axis without unpluggin it.
You now see the front of the unit. An ajustment screw, a green inspection lamp and a red one are present. The screw is use to adjust the idle speed and to change the diagnostic mode.
MARK THE ORIGINAL POSITION OF THIS SCREW. UPON DIAGNOSTIC COMPLETION, RETURN THE SCREW TO THE PREVIOUS POSITION. OTHERWISE, ENGINE IDLE SPEED MAY CHANGE.
2. The ECU modes
The electronic control unit have five mode:
Mode I- Exhaust gas sensor monitor (Normal mode)Mode II- Mixture ratio feedback control monitorMode III- Self-diagnosticMode IV- Switch on/off diagnostic systemMode V- Real-time diagnostics system.
The unit automatically return to normal mode I when the ignition is switched off.
Only mode III will be studied here. Troubles code are stored on mode III. The stored codes will be lost if the car battery is disconnected or if after selecting mode III, mode IV is selected.
3. Changing to mode III.
- Turn the ignition 'ON'- Turn the ECU adjusting screw fully clockwise.
The inspection lamps will flash onces, the unit will be in mode I. The inspection lamps will flash twice, the unit will be in mode II. The inspection lamps will flash 3 times, the unit will be in mode III. The unit will continually cycle through the five modes until the screw is turn back.
- Turn the screw back after the lamp has flashed 3 times.- You are now in self diagnostic mode III.
4. Reading the trouble codes.
The codes are indicated by the number of both red and green lamps. First the red lamp flashes and then the green one. The red lamp correspond to units of ten and the green lamp to units of one. For example, when the red lamp flashes once and the green lamp flashs twice, this signifies the number "12".
The codes are:11 Crank angle sensor circuit12 Air flow meter circuit13 Engine temperature sensor circuit14 Vehicle speed sensor circuit21 Ignition signal missing in primary coil31 E.C.U. (E.C.C.S. control unit)32* EGR function33 Exhaust gas O2 sensor circuit35* Exhaust gas temperature circuit43 Throttle position sensor circuit45* Injector leak55 No malfunction
*California models only.
After the diagnostic, Turn the ignition 'off' to return to mode I.
To erase the memory, use mode IV. The codes are automatically erased from memory when the starter is operated fifty times after the trouble is last noticed.
Hope it will help.
Richard [email protected]
How to read trouble code on your 240sx electronic control unit SOHC
******************************************************How to Read Malfunction Codes for Your SOHC 240SX=================================================On most car, only a jump wire or a screw driver is required to read the trouble code store on the engine computer. This the case for the 240 sx. The following intructions allow you to easily read and erase trouble code on your car electronic control unit (ECU)
The instructions come from the nissan 240sx 1989 12 valves engine service manual. There is a good chance that later models are similar.
In a few word, reading to code require accessing to the ECU, placing the unit in self diagnosis mode using a screw driver and looking at the flashing lamps on the unit to see what code is displayed.
1. Accessing to the ECU
The ECU is located to the right of the passenger footwell. You need to remove two fastener of the right doorstep in order to remove the kick panel. To remove the plastic fasteners, unscrew the center part and pull out the other part. Two metal screw and a fastener hold the kick panel. Some kind of pitch is also present.
Under the panel you now see the ECU with its connector. Unfortunaly, you have to access to the other side of the ECU. Unscrew the unit and turn it 180 degree on the vertical axis without unpluggin it.
You now see the front of the unit. An ajustment screw, a green inspection lamp and a red one are present. The screw is use to adjust the idle speed and to change the diagnostic mode.
MARK THE ORIGINAL POSITION OF THIS SCREW. UPON DIAGNOSTIC COMPLETION, RETURN THE SCREW TO THE PREVIOUS POSITION. OTHERWISE, ENGINE IDLE SPEED MAY CHANGE.
2. The ECU modes
The electronic control unit have five mode:
Mode I- Exhaust gas sensor monitor (Normal mode)Mode II- Mixture ratio feedback control monitorMode III- Self-diagnosticMode IV- Switch on/off diagnostic systemMode V- Real-time diagnostics system.
The unit automatically return to normal mode I when the ignition is switched off.
Only mode III will be studied here. Troubles code are stored on mode III. The stored codes will be lost if the car battery is disconnected or if after selecting mode III, mode IV is selected.
3. Changing to mode III.
- Turn the ignition 'ON'- Turn the ECU adjusting screw fully clockwise.
The inspection lamps will flash onces, the unit will be in mode I. The inspection lamps will flash twice, the unit will be in mode II. The inspection lamps will flash 3 times, the unit will be in mode III. The unit will continually cycle through the five modes until the screw is turn back.
- Turn the screw back after the lamp has flashed 3 times.- You are now in self diagnostic mode III.
4. Reading the trouble codes.
The codes are indicated by the number of both red and green lamps. First the red lamp flashes and then the green one. The red lamp correspond to units of ten and the green lamp to units of one. For example, when the red lamp flashes once and the green lamp flashs twice, this signifies the number "12".
The codes are:11 Crank angle sensor circuit12 Air flow meter circuit13 Engine temperature sensor circuit14 Vehicle speed sensor circuit21 Ignition signal missing in primary coil31 E.C.U. (E.C.C.S. control unit)32* EGR function33 Exhaust gas O2 sensor circuit35* Exhaust gas temperature circuit43 Throttle position sensor circuit45* Injector leak55 No malfunction
*California models only.
After the diagnostic, Turn the ignition 'off' to return to mode I.
To erase the memory, use mode IV. The codes are automatically erased from memory when the starter is operated fifty times after the trouble is last noticed.
Hope it will help.
Richard [email protected]
Re: ECU code 41... (vancouverbc)
Thanks for your help... just a last quetion.. then why is giving me the code 41 de ECU?? the problem that cause the car running bad is the air flow meter... but just wondering why that code...
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vancouverbc
- Posts: 3197
- Joined: Thu Oct 30, 2003 1:30 am
- Car: 1991 240sx
Re: ECU code 41... (JP240SX)
Im not sure
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donnie89240sx
- Posts: 63
- Joined: Mon Jun 04, 2007 4:41 pm
- Car: 1989 nissan 240sx coupe
Re: ECU code 41... (vancouverbc)
well i also have an 98 240sx with the sohc and my car gives me a code 41 also and yes it does have and intake air tep sensor its mounted in the air box by the mass air flow sensor. i know this because i spent 60 dollars replacing mine but that didnt help out it still came code 41 i just recent found out my ecu is bad.
Re: ECU code 41... (donnie89240sx)
sohc motors did have air temp sensors after a certain point.
check out the sohc FSM in my sig and go to the service bulletin section at the very end, it has information on the added air temp sensor and how to troubleshoot the code 41
check out the sohc FSM in my sig and go to the service bulletin section at the very end, it has information on the added air temp sensor and how to troubleshoot the code 41