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Re: 1996 lincoln town car p0403 code
Yes that is cat efficiency code for the bank2 (drivers side cat). When the PCM runs the cat efficiency monitor it compares the switch rate of the front O2 sensor with the rear O2 sensor to determine the ratio. If it falls below a programmed limit this code will set. There are usually 2 things that causes this. First is a lazy front O2 sensor, if your front O2 sensors have not been replaced in a while I would try replacing them first.
2nd is a bad catalytic convertor. If replacing the front O2 sensor does not correct your problem you will unfortunately need to replace the cat.
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OBD Code P0403refers to The Exhaust Gas Recirculation (EGR) system is controlled by a vacuum solenoid. The solenoid is supplied ignition voltage. The Powertrain Control Module (PCM) controls the vacuum solenoid by grounding the control circuit(ground) or driver. The primary function of the driver is to supply ground for the object that is being controlled. Each driver has a fault circuit that the PCM monitors. When the PCM turns a component on, the control circuit voltage is low, or close to zero. When the component is turned off, the voltage on the control circuit is high, or near battery voltage. The PCM watches for these conditions, and if it doesn\'t see the proper voltage at the proper time, this code is set.
Possible causes of OBD code P0403 The causes for a P0403 EGR code could be any of the following: Bad EGR solenoid Excessive resistance in control circuit (PCM controlled ground) due to an open, chafing or damage to the harness Poor connection at the EGR solenoid harness (worn or loose pins) Water intrusion at the EGR solenoid harness Blockage in EGR control solenoid holding solenoid open or closed causing excessive resistance Loss of supply voltage to EGR solenoid Bad PCM
code P0403 EGR ( exhaust gas recirculation ) valve solenoid malfunction, could be many things most likely would be just a bad control solenoid but could be the wiring to the solenoid, but most likely is not a bad EGR valve.
The EGR valve can be replaced by using a pipe wrench, or a standard wrench to remove the fitting over the pipe going into the EGR valve... it's not too hard to replace, I've done it on mine myself... I have a 97 town car as well... the only problem is that my EGR valve was fine, but the computer told me it was bad... But I found out that the EGR sensor was bad, not the valve... now to replace the EGR sensor you need to remove the engine... FORD in their infinite wisdom decided to put the EGR sensor on the rear of the engine, half way down next to the firewall...
My mechanic said that as long as the car is running fine, I souldnt worry about the EGR sensor, its job is to tell me when the EGR valve is bad...