1993 Vette "Change Oil" lamp after 1,207 miles
12-30-2017, 10:35 AM
#1
Heel & Toe
Thread Starter
1993 Vette "Change Oil" lamp after 1,207 miles
Hello and thank you for sharing your knowledge in previous posts. The "Change Oil" lamp has illuminated today but the oil has been changed 1,207 miles ago. The engine is at 41,007 miles.
I checked the dipstick and oil looks clean. Synthetic was put in last time at 39,800 miles.
On another note, the "Service Engine Soon" lamp has come on (once every 20 times driven) particularly when I've cruised at 80 mph or more..... but extinguishes at the next engine start up.
I really have to get a code reader....I think it's an OBD 1. Connector is a 12 pin.
Just learned how to get the codes...I get.... 1. C12 4. H43
I checked the dipstick and oil looks clean. Synthetic was put in last time at 39,800 miles.
On another note, the "Service Engine Soon" lamp has come on (once every 20 times driven) particularly when I've cruised at 80 mph or more..... but extinguishes at the next engine start up.
I really have to get a code reader....I think it's an OBD 1. Connector is a 12 pin.
Just learned how to get the codes...I get.... 1. C12 4. H43
Last edited by RubyRed40; 12-30-2017 at 11:21 AM. Reason: get codes using jumper wire
12-30-2017, 10:50 AM
#2
Race Director
You were supposed to have reset your change oil indicator back when you changed the oil. Now you have to reset it to turn out the light, then reset it again when you change the oil so its accurate.
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RubyRed40 (12-30-2017)
12-30-2017, 11:30 AM
#3
There is no oil analysis system on these cars, the light just comes on after a certain mileage. Resetting is easy and the procedure is in the sticky post at the top of this forum.
https://www.corvetteforum.com/forums...oil-light.html
As for the codes, use the search function. After a little search C12 is a control code meaning everything is working correctly, H43 is a knock sensor code in these cars so you can start there. Search H43 in the C4 forum and read until you have an idea of where to start.
https://www.corvetteforum.com/forums...oil-light.html
As for the codes, use the search function. After a little search C12 is a control code meaning everything is working correctly, H43 is a knock sensor code in these cars so you can start there. Search H43 in the C4 forum and read until you have an idea of where to start.
Last edited by thurman_merman; 12-30-2017 at 11:51 AM.
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RubyRed40 (12-30-2017)
12-30-2017, 06:10 PM
#4
According to the 90, 91, and 95 FSM's that I have read, there are several inputs to the calculation. (From memory, so probably not 100% perfect). Oil and coolant temperature at start up. Run time vs temperature. Number of crankshaft revolutions.
There is a channel in Module 4 for the "oil life counter". The FSM tells how to interpret this value. I don't recall right offhand.
Otherwise, no, it is not just a fixed mileage interval.
There is a channel in Module 4 for the "oil life counter". The FSM tells how to interpret this value. I don't recall right offhand.
Otherwise, no, it is not just a fixed mileage interval.
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RubyRed40 (12-31-2017)
12-31-2017, 05:02 AM
#5
with most of the above - reset your "light" and keep a mental note of the mileage for your next oil change. synthetic, probably at a minimum, 3-4K between changes. as for codes, member floridamale posted this several years ago - Code #12: Normal No Codes.
Code #13: Open Oxygen Sensor Circuit.
Code #14: Coolant Sensor Circuit Low.
Code #15: Coolant Sensor Circuit High.
Code #21: Throttle Position Sensor High.
Code #22: Throttle Position Sensor Low.
Code #23: Manifold Air Temperature Circuit High.
Code #24: Vehicle Speed Sensor.
Code #25: Manifold Air Temperature Circuit Low.
Code #32: EGR System Failure.
Code #33: Mass Air Flow Sensor High.
Code #34: Mass Air Flow Sensor Low.
Code #36: Mass Air Flow Sensor Burn-Off Function Fault.
Code #41: Cylinder Select Error.
Code #42: Electronic Spark Timing.
Code #43: Electronic Spark Control.
Code #44: Lean Exhaust indication.
Code #45: Rich Exhaust Indication.
Code #46: Vehicle Anti Theft Fault.
Code #51: Faulty Mem-Cal.
Code #52: Fuel Calpak Missing.
Code #52: (1990-91 Corvette Only): Engine Oil Temperature Sensor Low.
Code #53: System Over Voltage.
Code #54: Fuel Pump Circuit Low Voltage.
Code #55: Defective ECM.
Code #62: Engine Oil Temperature Sensor Circuit High.[/QUOTE]
#43 looks to be ESC - first step in the repair, get out the FSM. if you don't have a FSM, first step, get one -
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RubyRed40 (12-31-2017)
01-04-2018, 09:51 AM
#7
As joe c said - first step is to get a Factory Service Manual.
But since I happen to have a 92 FSM sitting here, and since there is no real difference in the system between 1992 & 1993 AND since it's about 20 degrees outside and snowing - I'll help you out a bit.
Factory Service manual says to disconnect both knock sensors, (they are accessible from below the car - they're threaded into what used to be called the block drains) - and with the ignition on - use a Digital voltmeter to verify that you have about 5 Volts between the wire and a good ground (check both sides).
If you have 5 Volts or so - check the resistance between the sensor and ground - it should be 3,300 - 4,500 ohms or so (again check both sides).
The odds are high that you have a knock sensor that's getting tired - so it might be a good idea to pick up a couple of knock sensors (they should be under $25/ea), and change them out. Note what I said above - these are threaded into the block drain holes - so when you take them out you're going to get a coolant bath - so you might as well do a full cooling system flush at the same time - so plan on also getting two gallons of (full strength) coolant, and a couple of gallons of distilled water, then drain the radiator, pull the block drains and let everything come out. It's not uncommon to get some really ugly junk out when the block drains are pulled. BTW - Since it's a 1993 - look at the radiator hoses and if they're marginal - this would be a great time to change them as well !!!
But since I happen to have a 92 FSM sitting here, and since there is no real difference in the system between 1992 & 1993 AND since it's about 20 degrees outside and snowing - I'll help you out a bit.
Factory Service manual says to disconnect both knock sensors, (they are accessible from below the car - they're threaded into what used to be called the block drains) - and with the ignition on - use a Digital voltmeter to verify that you have about 5 Volts between the wire and a good ground (check both sides).
If you have 5 Volts or so - check the resistance between the sensor and ground - it should be 3,300 - 4,500 ohms or so (again check both sides).
The odds are high that you have a knock sensor that's getting tired - so it might be a good idea to pick up a couple of knock sensors (they should be under $25/ea), and change them out. Note what I said above - these are threaded into the block drain holes - so when you take them out you're going to get a coolant bath - so you might as well do a full cooling system flush at the same time - so plan on also getting two gallons of (full strength) coolant, and a couple of gallons of distilled water, then drain the radiator, pull the block drains and let everything come out. It's not uncommon to get some really ugly junk out when the block drains are pulled. BTW - Since it's a 1993 - look at the radiator hoses and if they're marginal - this would be a great time to change them as well !!!