What is a Code 21?!?
Thread Starter
Burning Brakes
Joined: Feb 2001
Posts: 841
Likes: 0
From: Wichita, Ks, USA
What is a Code 21?!?
I keep having the check engine light come on at WOT so i paperclipped it and got a code 21. What is this code and how do i correct it? Moreover, wheres that website that has the complete list of GM trouble codes? My auto shop teacher is intrested in finding a rundown of them. TIA.
Melting Slicks
Joined: Nov 2000
Posts: 3,388
Likes: 1
From: X
Re: What is a Code 21?!? (Jsailor24)
Your TPS (throttle position sensor) is set to high. Needs to be adjusted.
To adjust it read here... https://www.corvetteforum.com/techti...D=55&TopicID=2
CODES=
12 Normal
13 O2 Sensor
14 Coolant Sensor (Low Voltage)
15 Coolant Sensor (High Voltage)
21 Throttle Position Sensor (High Voltage)
22 Throttle Position Sensor (Low Voltage)
24 Speed Sensor
32 FGR Vacuum Control (EGR)
33 Mass Air Flow Sensor
34 Mass Air Flow Sensor
42 Electronic Spark Timing
43 Electronic Spark Control
44 Lean Exhaust
45 Rich Exhaust
51 PROM Failure
52 CALPAK
55 ECM Failure
[Modified by JonM, 9:58 AM 5/7/2002]
To adjust it read here... https://www.corvetteforum.com/techti...D=55&TopicID=2
CODES=
12 Normal
13 O2 Sensor
14 Coolant Sensor (Low Voltage)
15 Coolant Sensor (High Voltage)
21 Throttle Position Sensor (High Voltage)
22 Throttle Position Sensor (Low Voltage)
24 Speed Sensor
32 FGR Vacuum Control (EGR)
33 Mass Air Flow Sensor
34 Mass Air Flow Sensor
42 Electronic Spark Timing
43 Electronic Spark Control
44 Lean Exhaust
45 Rich Exhaust
51 PROM Failure
52 CALPAK
55 ECM Failure
[Modified by JonM, 9:58 AM 5/7/2002]
Thread Starter
Burning Brakes
Joined: Feb 2001
Posts: 841
Likes: 0
From: Wichita, Ks, USA
Re: What is a Code 21?!? (JonM)
Thanks MUCH. Now this will cause me to loose performance because im turning it back? What are the correct voltage specs on the TPS at idle and WOT? Ive tried to do this myself and when i took it to a guy with a scanner after doing it, he said he had to adjust it because it was wrong. I guess ill take it to him again and ask him to reset it.
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: What is a Code 21?!? (Jsailor24)
Code 21 is the throttle positioning sensor high circiut. You should be reading about 5 volts at WOT. At closed throttle the voltage should be around .5 volts. The voltage should increase smoothly as the throttle is opeded. If the TPS circuit is shorted, the ECM thinks it is at WOT and will set code 21. Affects idle and fuel delivery. I can't help you on the website tho. Good Luck
[Modified by ittlfly, 7:05 AM 5/7/2002]
[Modified by ittlfly, 7:05 AM 5/7/2002]
