1993 gmc check light


Old 11-22-04, 06:29 PM
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1993 gmc check light

[FONT=check eng. soon light came on today and the first thing i notic was that the tranny was not shifting soomth. I did check the fuild. I turn the motor off for about an hour , I went out to go home and the check light was off. After about 20mins. the light was on and the shifting problem was back. Also it just turn 101,000 miles what could it be? ial Black]undefined[/FONT]
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Old 11-23-04, 04:31 AM
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You will need to read the codes to see where your problem is. Your vehicle will be OBD-I and you should be able to read them yourself. Locate your test connector. It will be a black plastic rectangular connector, probably under the dash by your left knee while seated in the driver's seat. Find the end of the plug that has two terminals side by side on one of the long sides. Take a paper clip and jumper these two terminals. Now turn on the key and watch the check engine light. COunt the flashes to read your codes. The first flashes will give you a code "12" and will be repeated more than once. This is just a code that tells you the diagnostics are working. Now count flashes for the other codes. They will be 2-digit codes and will use flashes spaced by brief pauses. For instance a 42 code would be flash-flash-flash-flash pause flash-flash. Each code will repeat before going to another code. For trasn codes you will be looking for numbers in the 60 & 70's. I'll post the tranny codes if I get the time. When the codes are done it will again flash the "12" code. Turn off key and remove jumper.
Old 11-23-04, 04:39 AM
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Trans codes:

58 or 59 Trans fluid temperature sensor
66 3-2 shift control solenoid
67 or 69 torque converter clutch solenoid
68 transmission slipping
72 vehicle speed sensor
73 pressure control solenoid
74 transmission input
79 transmission fluid temperature high
81 2-3 shift solenoid
82 1-2 shift solenoid
83 torque converter clutch
85 transmission gear
86 or 87 transmission gear ratio error

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