1995 Oldsmobile Aurora - Engine Light On with DTC code 049 Air Injection Reaction

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Asked by Mar 05, 2017 at 11:58 PM about the 1995 Oldsmobile Aurora 4 Dr STD Sedan

Question type: Maintenance & Repair

My 1995 Old Aurora is not OBD 1 and not OBD2, somewhere in between. The check engine light is on and the code read on the Actron reader is DTC 049. Only problem is that the Aurora service manual does not define what a code 049 is. The Actron says it is a "Air Injector Reaction" type error. I don't believe the 1995 Aurora uses an AIR pump to inject air into the exhaust during open loop operation, well at least I can't locate any pump. Any advice as to what this DTC 049 error is? BTW, I erase all the stored codes in the Actron, then start the car again. The service engine light illuminates and DTC 049 code is read again, so this issue does not appear to be a transient fault.

5 Answers

71,685

I don't think this is a valid code for your vehicle. Try flashing out the trouble codes using a paper clip. Do you know how to do that? To clear the computer (ECM) disconnect the negative (-) battery cable for 30 seconds. HTH. -Jim

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Hi Jim, I am not familiar with " flashing out the trouble codes using a paper clip" procedure, can you guide me? I did try disconnecting the battery fro 5 minutes, then reconnected and read the codes. The same 049 code came up as well as the Service Engine Light illuminated. Can you confirm for me, if you know, does this model year (1995 Aurora 4.0L) have an A.I.R. pump installed (if it does, where is it located)? I checked the two front wheel wells (perhaps the pump location for newer Auroras) and only found the horns.

1 of 1 people found this helpful.
71,685

I did not see a a listing for an air pump. So it's safe to assume you don't have one. To get the trouble codes use a large paper clip and install each end of the paper clip in the two holes in the upper right corner of the ALDL connector under the dash (the big plug that you connected the scan tool to with the ignition off. Once you have the paper clip inserted turn the ignition to the run position but don't try to start the engine. The check engine or service engine soon light, whichever you have, will begin flashing. It will first flash out reference code 12 to let you know that you are in diagnostics mode. Code 12 will be flash (pause), flash, flash. Each code will flash out three times before moving on to the next code. There will be a long pause in between each new code. For example if code 49 really is in there it will flash out as flash, flash, flash, flash, (pause) flash, flash, flash, flash, flash, flash, flash, flash, flash (long pause) then the next code. When code 12 begins flashing again all the codes have been flashed and you're starting from the beginning again. You can then turn off the ignition and remove the paper clip in that order. HTH. -Jim

20

Hi Jim, Thanks for explaining the "paper clip" procedure. Turns out that I solved my problem, and I have to admit, it's partly me being a doofus. Let me explain, first some back ground. Last weekend I replaced the idler pulley on the serpentine belt tensioner. That procedure went fairly smoothly. However, it required me to disassemble the front left motor mount and attaching plate to the motor. What I didn't realize at the time was as I wiggled the cumbersome plate out and away of position to gain access to the belt and pulley assembly, I inadvertently caused a wire plug to dislodge from it's socket due to the force of the plate being shoved aside. Today I retraced the steps I took during the repair procedure, since the car was just running fine with no error codes before I changed the pulley. As I checked around the engine compartment near the back left side of the engine, I happened to see a blue colored, I believe gasket, visible near the end of a wire. That seemed odd to me. So I shined a bright light in the gap between the engine and left fender wheel well. Lo and behold, the wire's plug was mostly dislodged from it's mating socket. Turns out this is the wire connection for the cam shaft position sensor (CMP). So the cam shaft position sensor was completely disconnected and apparently detected as such by the PCM. Whats odd is that the PCM recorded a "bogus" DTC code 049 as read by my Actron scanner instead of a more revealing and helpful DTC code 041. Suffice it to say, after seating the plug back into it's socket the check engine light is now off and no trouble codes are present in the PCM. Anyway, thanks for your help on this. I wonder though if the "paper clip" code reading method could have provided a more accurate DTC code for this issue. I'll have to try that later to see. Oh, one other question...in the future I'm thinking about using OBD scan software on a laptop to read the codes. For the cable connection, I believe there is a way to jumper certain pins on the data link connector to be able to read the DTC codes on a laptop. Maybe the UART pin 9 and the PCM GND pin 5 are connected to a RS232 pin 2 and pin 5 on the laptop? Do you have any experience with this, any recommendations? Thank you.

1 of 1 people found this helpful.
71,685

WOW!! So glad you retraced your steps and found the problem!! Good job!! I've had that happen to me as well. I'll fix something then when it's all buttoned up something else will be going on leaving me scratching my head and saying it wasn't doing THAT before!! So you're definitely not alone there!! Unfortunately on GM OBD I systems I've only used the paper clip method. I have an Actron code reader as well that will (supposedly) do anything US made 1982 and forward, OBD I and OBD II. I've actually only used it on OBD II equipped vehicles. So unfortunately I have no experience using a laptop for troubleshooting. It is an excellent set up to have though especially for intermittent problems. You can see exactly what's going on when the vehicle acts up! Thanks very much for sharing your experience!! HTH. -Jim

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