I am still driving around with the "Check Engine" light on. I have codes 5 and 26. I should probably start by cleaning the EGR pipe. Could anyone give me some direction on how to locate it and what to do?

Here's a list of codes that I got from another message:

1 No malfunction in system monitored
2 Heated O2 sensor inoperative
3 Lambda control inoperative
4 Air injection inoperative
5 Exhaust gas recirculation inoperative
6 Idle speed control inoperative
7 Ignition system defective
8 Engine coolant temp. sensor, open/short circuit
9 Intake air temp. sensor, open/short circuit
10 Voltage at hot wire mass air flow sensor too high/low
11 TN-signal (rpm) at engine control module (N3/4) defective
12 Heated O2 sensor heater, open/short circuit
15 Wide open throttle information defective
21 Bad Purge Switch-Over Valve

Could somebody fill out the rest so we have a complete list. I am looking for code 26