Code 12 -Idle Air Bypass motor not controlling idle properly (generally idle too low) - IAB dirty or not working. Take it off and clean it thoroughly with throttle body cleaner. Clean the electrical contacts with non flammable brake parts cleaner at the same time.
Code 32
Revised 22Nov-2009 to include at rest voltage specs for EGR output voltage.
EGR voltage below closed limit. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit. Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or MAP sensor located on the firewall near the center of the car. Use the black/white wire for the ground for the DVM.
Let’s put on our Inspector Gadget propeller head beanies and think about how this works:
The EGR sensor is a variable resistor with ground on one leg and Vref (5 volts) on the other. Its’ resistance ranges from 4000 to 5500 Ohms measured between Vref & ground, depending on the sensor. The center connection of the variable resistor is the slider that moves in response to the amount of vacuum applied. The slider has some minimum value of resistance greater than 100 ohms so that the computer always sees a voltage present at its’ input. If the value was 0 ohms, there would be no voltage output. Then the computer would not be able to distinguish between a properly functioning sensor and one that had a broken wire or bad connection. The EGR I have in hand reads 700 Ohms between the slider (EPV) and ground (SIG RTN) at rest with no vacuum applied.
As vacuum is applied, the voltage on the slider increases (EVP). As the voltage increases, the computer knows the how much the EGR valve is opened and how much exhaust gas is being recirculated. It uses the load table to calculate the amount of exhaust gas required depending on RPM, Mass Air Flow, ACT, ECT & TPS. It then sends a signal to the Electronic Vacuum Regulator to hold, increase or decrease the vacuum being applied to the EGR valve.
Theory class is over now, let’s spin up our propeller head beanies and get with it… Go Gadget, Go…
Remember that resistance checks are always done with the power off the circuit.
Measure the resistance of the EGR sensor between the two end pins. You should see between 3500 to 5500 Ohms. With the sensor removed, measure the resistance again while pressing on the plunger. You should see the resistance drop from its high value to a low reading of 200-700 ohms depending on the sensor. No resistance readings, or values way out of range, the sensor is bad.
If the Orange white wire has Vref, (5 volts =/-.25 volt) then you have some wiring problems because the computer isn’t seeing the minimum voltage on the EVR pin. Ohm the wiring back to the computer. Check for resistance between the brown/lt green wire on the EGR sensor and pin 27 on the computer: you should have less than 1 ohm. Repeat the process for the orange/white wire and pin 26. Do it again between the black/white wire and pin 46. In no case should you have more than 1 ohm.
Ignition switch in the run position but the engine not running voltage tests.
The brown/lt green wire should show between .25-.67 volts with ignition switch in the run position but the engine not running.
Voltage and resistance checks are good: Here’s an EGR test procedure I copied from cjones
EGR test procedure
to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve or
see the EGR test jig drawing below. Connnect the test jig or to directly to manifold vacuum.
Do not connect the EGR test jig to the EVR (Electronic Vacuum Regulator).
apply 5in vacuum to the valve.
Using the test jig, use your finger to vary the vacuum
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled,
connect EGR test jig to the hose coming off of the EGR Valve.
Use your finger to cap the open port on the vacuum tee.
snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
did the vacuum gauge show about 2-5 in vacuum?
if not the EVR has failed
EGR test jig
If the test procedure fails to provide proper vacuum, check vacuum feed lines for cracks & damage. If the vacuum lines are good, check the electrical wiring to the EVR. If the EVR electrical wiring is good, look for 12 volts on the red wire for the EVR. If the 12 volts is good, look for a varying voltage on the dark green wire on the EVR. Case of last resort, replace the EVR and then the computer