Questions and Answers

Dodge Shadow Codes 15 And 21 Q. Hello, I have some doubts about the stored codes in my car, because I only saw the Check Engine Light (CEL) sometimes when I made a wash service engine, but later disappear in the next switch off. Only for curiosity I tried to obtain them and the final result was two returned codes, the numbers 15 and 21.

I'm the owner of this car since 3 year ago and never has been repaired for some kind of a storage code, of course all the rest of the reparations was made it for maintenance and by the normal wear.

Please tell me, it's necessary to correct it or what I need to do? Because I feel fine the car and it's used daily 38 miles and I don't know which can be the impact of this in the car. By other side I don't want to spend some money unnecessarily.

• 1993 Dodge Shadow
• 2.5 liter
• Automatic Transmission
• 140,000 miles
• Fuel injection
• No : ABS - A/C

Sorry for my bad english and thank you very much in advance for your help.

Best regards From México City.

A. Okay, these are what code 15 and 21 are.

• 15 - No vehicle speed signal. No vehicle distance (speed) sensor signal detected during road load conditions.
• 21 - Oxygen sensor signal. Neither rich nor lean condition is detected from the oxygen sensor input.

So code 15 is saying that the Powertrain Control Module (PCM) is not getting a signal from the Vehicle Speed Sensor (VSS). This is probably due to a bad VSS or wiring problem. This would also cause problems with the speedometer and cruise control (if equipped).

Sensor mounted in transaxle extension housing

Code 21 is saying that the PCM is not getting a signal from the Oxygen Sensor (HO2S), again, due to a bad sensor or wiring problem.

Both of these sensors effect engine performance and fuel economy, so it would be a good idea to repair them.

Sensor threaded into exhaust manifold