check engine light-driving method to clear module

[FirstHSE]

Issue - an inconsistent check engine light.

My question - is there a particular way to drive a 2001 HSE to clear the modules after everything has been reset?

Situation leading up to this problem - about a year ago the light came on a few days after taking the car off road on a dealer's excursion day. At that time, my mechanic did a diagnostic three times - no codes. So, I just drove the car with the light on. Every time I went in for service, everything was reset. Light would go out. The next day I turned on the car and drove a few miles, the light reappeared. Otherwise, the car runs great. Now, I need a smog clearance.

Hook up the smog machine - I have 4 codes that appear:P1172 & P1175, and P0174 & P0171 (lean) which I found addressed in a previous thread 2001 Range Rover HSE Check Engine Light .

My mechanic suggests that I replace the ignition coil & spark plug wires. He estimates $1500 - I looked up the two parts which come to about $150. Maybe he's going to do more work than just those items to fix the problem...?....

Plug wire set GWS102 $44.50
Coil pack ERR6045 $89.50
Shipping about $12 by UPS.

Here's what is strange - he resets and clears everything - no light. I drive 50 miles mostly fwy and some street. No check engine light. But, when the smog guy hooks up the machine while the car is still running, the four codes are displayed. I turn off the car. Turn it back on, drive 2 miles and the light appears. The smog guy said that there are different ways to drive cars to clear out the module. Ex: Japanese car - Drive it in the morning about 10 miles to get it warmed up. He saw a book one time that outlined the method for each manufacturer but didn't buy it.

Can anyone tell me how to drive a 2001 RR to clear the module?

I welcome your suggestions regarding any part of my problem.

Thank you.

[hermanpj]

you are talking about drive cycles. somebody might know what the drive cycles are to put the car through all the driving conditions in sequence in the least amount of time.

easiset just to buy a diagnostic code reader than can clear the codes. $50 bucks or less.

changing the wires and plugs is not a big deal. the problem w coil pack is it requires removal of the intake plennum to access it. assuming 100% markup on parts, the roughly 1200 labor estimate seems excessive. periodically a rover tech is on this board and could maybe tell you how many hours he thinks replacing coil pack, wires and plugs should be budgeted for.