97 Camaro V6 Error codes P0123 P0118 P1406

clear codes start run and see what codes return.need to do some circuit checks.codes do not mean to change sensor or component.chance of multiple sensors going bad all at once is slim to none.do you have a dc meter and tpins?

I have tried to clear the codes and P1406, P0118 will clear but P0123 stays non stop. Yes i have a meter and and tpins. The tps reads 5.6v going to it, ground shows 4.6v and sending 2.6 to comp.

Ground is suppose to be .0v right so thos means bad wiring like ground? Oh some squirrels chewed through the O2 sensor on exhaust before manifold. I spliced and taped up wires together will that cause any bad readings?. The same with the speed sensor on transmission. If its spliced would that cause the car to shift and idel down real slowly. When it shifts from 1 to 2 i have to stomp the gas so the rpms get over 5000 and it will finally shift.

so you have p1406 and p0123.use battery negative terminal for meter negative connection when doing and voltage checks or ground to ground checks......best ground on car.meter neg to battery neg and back probe tps all three terminals with tpins and touch meter pos to each wire key on engine off.......should have close to 5 volts on ref wire and around .50-.75 volts on signal wire and under .10 or 100 mv. on ground wire.make sure to use battery neg for meter neg connection for all three voltage checks.let me know results.I will check wiring diagram for shared ground for egr and tps.you could have a problem with the 3 wire potentiometer on the egr circuit.on newer vehicles the pcm will use substituted values if it detects a faulty sensor but older pcms were not as smart.vss is important for shifting.do you have access to a scan tool with data stream?

the tps and the egr potentiometer share the same ground.let me know tests above I mentioned and then we can test the egr 3 wire potentiometer circuit.

Sorry I missed your reply that p1406 does not set. Just p0123. Do voltage checks as described above and post.

Okay sorry with key in on position ref wire reads 5.5 v , signal wire 0.0, ground 4.8v. Bad ground ?

Can i run a new ground just a single ground and connect all sensors to it?

Update: i grounded the tps and the iat sensor and now 3 codes came up P0123, P1406, P1406. I was able to clear codes and read the comp again and it said 0 codes det. The ses light stays on though

the sensor ground has to run back to pcm.would have to check back probed at the pcm terminal and see if high there.........if so then pcm sensor external ground connection or bad pcm.if low voltage at pcm then open ground from pcm to tps.a thermistor (iat)cant share ground.there should be a ground stud in engine compartment......neg meter to battery neg and pos to this stud and should be less than 100 mv or .10.also at pcm terminals for egr and tps ground.I cant look up pcm terminals till later tonight.....work all day.do you want me to look up pcm connector terminal numbers for egr and tps for you?

Thank you for the tip i never checked the reading at the pcm connect. I did check the pinout for my year and my car is wired different then it shows. Somebody has done a number. Ill check the reAding at the pcm. Oh when i did run a temp ground from tps and iat the codes cleared and the ses light stayed off. If i removed either ground the light comes on. Ill post the results later. Thank you again for your time and info its alwalys worth a sec pair of eyes or advice.

sensor grounds are fed to pcm board and then pcm has external grounds.you can't bypass them.c1 pcm connector which is blue pin 56 black wire is sensor ground wire to pcm board.check pos meter back probed there with tpin and neg meter to battery neg terminal key on engine off.........if you need a pcm pin number diagram send me you email and I can send to you.there is a ground splice s119 that feed egr/tps/ect/map/tft/ac pressure sensor then feeds to pcm sensor ground pin 56 as mentioned above.if you have a low voltage on pin 56 then possible bad ground splice connection at slice s119.location of slice s119 is engine harness main branch approx 6 cm from injector number 1 breakout.just follow the tps ground wire black wire from terminal a through harness to splice.now if you got high voltage at pcm pin 56 then would have to check external pcm grounds and if good then replace pcm and if not good have to clean and repair them.It is a step by step process of elimination.I can guide you in the process.let me know.

also take and tpin terminal b black wire at egr connector and see what the voltage is key on engine off using battery neg for meter neg connection......should be less than .10

i also misstated above when said thermistors cant share ground......they cant share signal wire.

Sorry just been really busy. I checked the signal ground for sensors num 56 blue pinout. It was reading .02 so i ran a new ground wire from tps, ect, and iat to num 56. I left the origional ground in place just spliced in a new one. Now ses light off, no codes appear, and she runs good. Went to smog her after driving about 15 miles and they said all mods werent set yet to go drive it another 30-40 miles and bring it back in and it should be set. Now by running those three new grounds it doesnt solve the short, so is it gonna damage the engine to have it with still a short even with the new grounds? Thankyou autojoe you have sent me in the right direction and helped me see what i had been missing. I really do appreciate all the help and advice thank you again

there is no short you have an open ground circuit.the splice s119 connection may just need cleaned and check connection.that is probably your whole problem.your not going to damage engine......just codes return.good luck

The codes will return even with the new ground? Thank you for letting me know you said to check s119 i will do that. It passed smog thankfully. I will do that and again you have been awesome thank you again.

if you ran a separate ground wire to computer eliminating the bad ground wire you should be okay.I would have just fixed the bad ground location problem thus fixing the problem.I would check ground to ground voltage drop testing neg meter on battery neg and pos meter on ground terminal of the individual sensors like egr/tps/iat back probed koeo and if all sensor grounds have high voltage then trace to slice s119 and check voltage at that splice and if high then clean and repair.good luck and let me know if further assistance is needed.you said you spliced wires......I either solder and tape but most time I use a butt connector that you crimp and then use a heat gun or lighter and shrink ends to make tight connection.good luck.