2002 CADILLAC DEVILLE CODE P0412

Ull need to scanit w a factorytool at a privateshop. It reads a datastream to pinpoint issues. Those portabl readers are general. Dont just replaceparts n hope. Oldercars can hav worn wireharness causin weird problms too. Unplug computer n cleanpins..dirt is common in aging vehicles creating issues. Since its jyst an emmission thing udont need to worry its runnin too lean or sumthin crucial

This is the electrically driven secondary air injection air pump. Please read all the information at the link before you buy or replace any parts. In most cases the entire air injection pump assembly must be replaced.
P0412 Secondary Air Injection System Switching Valve Circuit Malfunction

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code p0412 refers to secondary air injection (AIR) solenoid A---circuit malfunction===causes wiring---air solenoid---ECM
replace the AIR solenoid.

There is no unlock code - each radio is programmed with the VIN of the vehicle in which it was last installed. The only way to reprogram it to a different vehicle is with a Tech II scan tool (GM Dealer).

I'm going to post the description from engine-codes.com since it is a big paragraph. You will need a shop manual or else take it to a repair shop that has the equipment and book to check it out.

P0412 TOYOTA Description
An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations id desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.
The DTC P0412 is detected the the AIR vacuum control solenoid circuit not operating as desired by the PCM.
Read more: http://engine-codes.com/p0412_toyota.html#ixzz2Y7OQTCbb

This switch opens the starter circuit when the transmission is in any gear but Neutral or Park on automatic transmissions.


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P0412 - Secondary Air Injection System Switching Valve 'A' Circuit Malfunction

Possible causes- Faulty Air Pump inoperative
- Air bypass solenoid harness is open or shorted
- Air bypass solenoid circuit poor electrical connection

A vehicle speed sensor bad MAY cause that code. Its located near where the right axle comes out of the transmission.

P0412 Secondary Air Injection System Switching Valve A Circuit Malfunction

Possible Causes

Short to power or ground in the AIR command circuit.

Open in the AIR command circuit.

AIR bypass solenoid fault.

AIR relay fault.

Damaged PCM.