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Unread 11-07-2013, 09:05 PM   #1
weswilliams
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1996 ZJ 
 
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What does the check engine light codes mean

So i'm new to being able to check the check engine light codes by just numbers showing up on the odo. I got the codes 12 and 37. Can anyone help tell me what they mean? Also, when I've taken cars to get checked with a scanner the codes come up as P0407. How can you convert one to the other so you can read them as the same?
Thanks

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Unread 11-07-2013, 09:12 PM   #2
ZeeJay1997
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Dont worry about the 12

37* P0740
Torque Conv Clutch, No RPM Drop At Lockup
Relationship between engine speed and vehicle speed indicates no torque converter clutch engagement (auto. trans. only).

Are you feeling torque convertor lockup at 45 mph?

you should have had a 55 at the end of codes.
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Unread 11-07-2013, 09:29 PM   #3
JasonStebbins
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1997 ZJ 
 
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1995 and earlier have ODB1 systems. You can access these codes by doing the key trick, some models show up on the odometer like yours. 1996 and later have ODB2 systems that have four letter codes read by a scan tool. Check the sensors and wiring on the side of the transmission. One might be loose or needs to be cleaned. Otherwise it sounds like your TC is shot. I read on here once that somebody had these codes and ended up replacing the TPS to fix the problem. Just a thought.

11

No crank reference signal detected during engine cranking. Intermittent loss of either camshaft or crankshaft position sensor. CKP sensor target windows have too much variation.

12

Direct battery input to PCM was disconnected within the last 50 Key-on cycles.

13

No difference recognized between the engine MAP reading and the barometric (atmosphere) pressure reading from start-up.

14

MAP sensor input above or below acceptable voltage. 5 volt output to MAP sensor open.

15

No vehicle speed sensor signal detected during road load conditions.

17

Engine did not reach operating temperature within acceptable limits. Engine does not reach 20º F. within 5 minutes with a vehicle speed signal.

21

Upstream oxygen sensor response slower than minimum required switching frequency. Upstream oxygen sensor heating element circuit malfunction. Downstream oxygen sensor heating element circuit malfunction. Downstream oxygen sensor input voltage maintained above the normal operating range. Oxygen sensor voltage too low, tested after cold start. (Upstream or Downstream) Left oxygen sensor input voltage maintained above the normal operating temperature.

22

Engine coolant temperature sensor above or below acceptable voltage.

23

Intake air temperature sensor input above or below acceptable voltage.

24

Throttle position sensor input above or below acceptable voltage. TPS signal does not correlate to MAP sensor.

25

A shorted or open condition detected in one or more of the idle air control motor circuits. Actual idle speed does not equal target idle speed.

27

Injector #3, and/or 4, and/or 5, and/or 6 output driver does not respond properly to the control signal.

31

An open or shorted condition detected in the A/C clutch relay circuit. Insufficient or excessive vapor flow detected during evaporative emission system operation.

33

An open or shorted condition detected in the duty cycle purge solenoid circuit. (A/C clutch relay circuit)

34

An open or shorted condition detected in the Speed Control vacuum or vent solenoid circuits. Speed control switch input below the minimum acceptable voltage.

37

Relationship between engine speed and vehicle speed indicates no torque converter clutch engagement. An open or shorted condition detected in the torque converter part throttle unlock solenoid control circuit. Incorrect input state detected for the Park/Neutral switch. Auto only.

41

An open or shorted condition in the generator field control circuit.

42

An open or shorted condition detected in the auto shutdown relay circuit. An open condition detected in the ASD relay output circuit. An open or shorted condition detected in the fuel pump relay control circuit. An open circuit between PCM and fuel gauge sending unit. Circuit shorted to voltage between PCM and fuel gauge sending unit. No movement of fuel level sender detected.

43

Peak primary circuit current not achieved with maximum dwell time. Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)

44

Battery temperature sensor in voltage above or below acceptable range.

46

Battery voltage sense input above target charging voltage during engine operation.

47

Battery voltage sense input below target charging during engine operation. Also, no significant change detected in battery voltage during active test of generator output circuit.

51

A lean air/fuel mixture has been indicated by an abnormally rich correction factor.

52

A rich air/fuel mixture has been indicated by an abnormally rich correction factor.

53

PCM Internal fault condition detected.

54

No camshaft signal detected during engine cranking.

55

Completion of fault code display on Check Engine lamp.

62

PCM Failure to update service reminder indicator

63

Unsuccessful attempt to write to an EEPROM location by the PCM.

64

Catalyst efficiency below required level. (Same as code 72)

65

Power steering high pressure seen at high speed. (2.5L only)

72

Catalyst efficiency below required level. (Same as code 64)

77

Malfunction detected with poser feed to speed control servo solenoids.
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Unread 11-07-2013, 09:41 PM   #4
ZeeJay1997
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Quote:
Originally Posted by weswilliams View Post
How can you convert one to the other so you can read them as the same?
The Malfunction Indicator Codes (MILs) may be caused by one or more P codes or scan tool codes. Each scan tool code has a unique MIL code.

For instance a MIL 22 could be P0117 ECT Sensor Voltage Too Low or P0118 ECT Sensor Voltage Too High.
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Unread 11-07-2013, 11:22 PM   #5
weswilliams
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It's a 4x4 and I was sitting in the car for a few minutes after I turned it off, before leaving it alone to come back and crank it and see the check engine light on. However while i was sitting in the car after it was turned off I think I may have bumped the 4x4 lever into between 2wd and N, however it drove fine. Could that be the issue? I'll try to adjust it when getting in tomorrow morning to see if the problem ceases.
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Unread 11-08-2013, 12:23 PM   #6
Oldfrog
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My 97 codes can be read using the key trick...so I guess it runs up to the 98 model where it doesnt work.
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Unread 11-08-2013, 01:35 PM   #7
zj97ltd
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My wife's 04 Durango still uses the key trick for codes.
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Unread 11-08-2013, 08:31 PM   #8
weswilliams
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Quote:
Originally Posted by ZeeJay1997 View Post
Dont worry about the 12

37* P0740
Torque Conv Clutch, No RPM Drop At Lockup
Relationship between engine speed and vehicle speed indicates no torque converter clutch engagement (auto. trans. only).

Are you feeling torque convertor lockup at 45 mph?

you should have had a 55 at the end of codes.

I got the 55 at the end. But I'm not feeling any difference past 45 mph, and I've been up to about 75 since with no issues. It's driving totally fine. Any ideas?
Thanks again
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Unread 11-08-2013, 09:03 PM   #9
ZeeJay1997
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if you start out with a steady accelerator and let it shift through and you dont feel it shift (should feel like 5th gear), the convertor is not locking up.

as someone else mentioned, you should be able to hold the accelerator steady at cruise speed, barely touch the brake with the left foot, and see the tach jump.

this is not happening, your convertor is not locking up. most likely due to bad solenoid in tranny. i
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Unread 11-10-2013, 10:33 PM   #10
weswilliams
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Update: The check engine light went off on its own!
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Unread 11-15-2013, 10:35 PM   #11
weswilliams
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Update: It came back on and this time I managed to get it checked before it did. Turns out the torque converter is going out. It still has a fair amount of life left in it though because I'm having no issue with power coming as the rpms raise.
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Unread 11-16-2013, 06:02 AM   #12
ZeeJay1997
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a code for the convertor does not necessarily mean the convertor is going out. it could be and most likely is electrical if you're driving okay. you can try cleaning the PCM connectors and connector on top of transmission.

Do this test and let us know what you find,

CONVERTER STALL TEST
Stall testing involves determining maximum
engine speed obtainable at full throttle with the rear
wheels locked and the transmission in D range. This
test checks the holding ability of the converter overrunning
and transmission clutches.
WARNING: NEVER ALLOW ANYONE TO STAND
DIRECTLY IN LINE WITH THE VEHICLE FRONT OR
REAR DURING A STALL TEST. ALWAYS BLOCK
THE WHEELS AND FULLY APPLY THE SERVICE
AND PARKING BRAKES DURING THE TEST.

STALL TEST PROCEDURE
(1) Connect tachometer to engine. Position tachometer
so it can be viewed from driver’s seat.
(2) Drive vehicle to bring transmission fluid up to
normal operating temperature. Vehicle can be driven
on road or on chassis dynamometer, if available.
(3) Check transmission fluid level. Add fluid if necessary.
(4) Block front wheels.
(5) Fully apply service and parking brakes.
FSM left this out: Place shifter in Drive
(6) Open throttle completely and record maximum
engine speed registered on tachometer. It takes 4-10
seconds to reach max rpm. Once max rpm has
been achieved, do not hold wide open throttle
for more than 4-5 seconds.

CAUTION: Stalling the converter causes a rapid
increase in fluid temperature. To avoid fluid overheating,
hold the engine at maximum rpm for no
more than 5 seconds. If engine exceeds 2500 rpm
during the test, release the accelerator pedal immediately;
transmission clutch slippage is occurring.

(7) If a second stall test is required, cool down
fluid before proceeding. Shift into NEUTRAL and run
engine at 1000 rpm for 20-30 seconds to cool fluid.

STALL TEST ANALYSIS
Stall Speed Too High
If the stall speed exceeds 2500 rpm, transmission
clutch slippage is indicated.

Stall Speed Low
Low stall speed with a properly tuned engine indicate
a torque converter overrunning clutch problem.
The condition should be confirmed by road testing. A
stall speed 250-350 rpm below normal indicates the
converter overrunning clutch is slipping. The vehicle
also exhibits poor acceleration but operates normally
once highway cruise speeds are reached. Torque converter
replacement will be necessary.

Stall Speed Normal But Acceleration Poor
If stall speeds are normal (1800-2300 rpm) but
abnormal throttle opening is required for acceleration,
or to maintain cruise speed, the converter overrunning
clutch is seized. The torque converter will
have to be replaced.

Converter Noise During Test
A whining noise caused by fluid flow is normal during
a stall test. However, loud metallic noises indicate
a damaged converter. To confirm that the noise
is originating from the converter, operate the vehicle
at light throttle in DRIVE and NEUTRAL on a hoist
and listen for noise coming from the converter housing.
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Unread 11-16-2013, 06:29 AM   #13
bigbill888
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Location: michigan
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Don't let a mechanic tell you that your torque converter is "going out". It's probably something way simpler and way cheaper. I'm guessing a torque converter replacement is $800.
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Unread 11-16-2013, 09:03 PM   #14
weswilliams
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Alright will do, thanks guys
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Unread 11-17-2013, 07:40 AM   #15
Snowfan2
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Newegg sells a code scanner that clears codes for 20 bucks. I have one, works great.
http://www.newegg.com/Product/Produc...9SIA0XA0851767
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