Drive Cycle
03-29-2018, 07:07 PM
#1
Rennlist Member
Thread Starter
Drive Cycle
No longer have a 993, but my neighbor does. He is getting these codes:
Cat Monitor
Evap System Monitor
Secondary Air System
O2 Sensor Monitor
O2 Sensor Heater Monitor
Can he get these cleared with a drive cycle? If so, what is the latest recommended drive cycle. You can PM me, or email me and I will forward it to him. My email is:
mfschacht@gmail.com
Thanks in advance.
Cat Monitor
Evap System Monitor
Secondary Air System
O2 Sensor Monitor
O2 Sensor Heater Monitor
Can he get these cleared with a drive cycle? If so, what is the latest recommended drive cycle. You can PM me, or email me and I will forward it to him. My email is:
mfschacht@gmail.com
Thanks in advance.
03-29-2018, 09:18 PM
#2
A healthy 993 will reset all those codes with the normal bmw drive cycle. There is a thread right above this one with the instructions or through google. Keep in mind, cycles need to be done at least twice with a complete cool down in between (I.e. overnight).
03-29-2018, 09:41 PM
#3
Instructor
I tired the BMW cycle on my 97 by the book at least twice, result was no go! Some of the monitors would not set. So I gave up on it, over time periodically drove it here n there, few mo later when I was up for smog check, plugged in the OBD reader, to my suprize it was all good. Honestly driving it a for a week, daily commute might do the trick also.
03-29-2018, 10:52 PM
#4
Three Wheelin'
As said somewhere in the sticky thread above, it depends on the year. 96 are much more difficult than 97 and 98. But the consensus is to use the BMW cycle and it may take many attempts. A 96 will probably never just magically pass for just driving....
03-30-2018, 12:33 PM
#5
Rennlist Member
All of those items must be replaced. Once I fixed mine, it consistently takes one BMW drive cycle to reset the codes on my 96.
I am very careful to never exceed 3000 RPM during the entire trip. I do not even have to and idle for 5-mins at the end, the codes reset as soon as I stop. I know this because I have the OBD2 reader plugged-in before starting the car up.
I am very careful to never exceed 3000 RPM during the entire trip. I do not even have to and idle for 5-mins at the end, the codes reset as soon as I stop. I know this because I have the OBD2 reader plugged-in before starting the car up.
03-30-2018, 12:46 PM
#6
Last I checked for 1996-2000 vehicles:
- There are only 2 places in the US (Lake and Porter counties in Indiana) that require all 5 monitors to be READY in order to get tested.
- CA is the next toughest where only EVAP can be NOT READY.
- In all other's, you can have TWO monitors NOT READY.
Your friend will still need to drive around, but getting 3 or 4 monitors ready will be easier than getting all 5.
BTW, I intentionally take my 97 C2S to emissions with the AIR monitor NOT READY - this masks my SAI faults. (No SAI codes can get thrown until the AIR monitor is READY).
- There are only 2 places in the US (Lake and Porter counties in Indiana) that require all 5 monitors to be READY in order to get tested.
- CA is the next toughest where only EVAP can be NOT READY.
- In all other's, you can have TWO monitors NOT READY.
Your friend will still need to drive around, but getting 3 or 4 monitors ready will be easier than getting all 5.
BTW, I intentionally take my 97 C2S to emissions with the AIR monitor NOT READY - this masks my SAI faults. (No SAI codes can get thrown until the AIR monitor is READY).
03-30-2018, 02:25 PM
#7
Having a healthy car with decent O2 sensors, EVAP and SAI system is the key.
Trending Topics
03-30-2018, 02:33 PM
#8
Three Wheelin'
First, it's not one person's experience; many have said the same on the sticky thread above. Second, from what I've been told, the software was changed to -- in laymen's terms -- be less finicky. If you know -- KNOW -- differently, I'm all ears. Otherwise, I'll go with the mechanics I've talked with about this.
03-30-2018, 07:53 PM
#10
Originally Posted by SwayBar
All of those items must be replaced.
These threads regularly come up in the spring when people are removing their cars from hibernation.
03-31-2018, 12:16 PM
#11
No. It's FAR more likely that he just disconnected the battery and needs to run the cycle. You're talking THOUSANDS to replace all those systems when it'll likely be fixed (or at the very least reduced) for just a little gas, time, and patience.
These threads regularly come up in the spring when people are removing their cars from hibernation.
These threads regularly come up in the spring when people are removing their cars from hibernation.
Much of the confusion about monitors would be eliminated if people understood a basic principle of OBD2: emissions stations aren't really "testing" anything - they're just reading out the results of the tests your car did on itself. Basically, they're an expensive print service and network connection. When cars get internet connections they'll be both self-testing AND self-reporting and emissions stations will be a thing of the past.
03-31-2018, 12:46 PM
#12
Read here: http://www.systemsc.com/codes.htm
6. Some early OBDII vehicles, e.g. Porsche 993 ('96), may require three trips as in #1 above
versus two trips for later vehicles ('97), e.g. updated firmware, and/or may also require a waiver
from the emissions regulatory agency. Also, some of these early vehicles may reset the readiness
codes at engine shut-down before completion of a trip requiring the starting of another new trip.
If a cycle fails, e.g. EVAP or SAI, during a subsequent trip but before completion of all necessary
trips, the required number of trips must be restarted.
versus two trips for later vehicles ('97), e.g. updated firmware, and/or may also require a waiver
from the emissions regulatory agency. Also, some of these early vehicles may reset the readiness
codes at engine shut-down before completion of a trip requiring the starting of another new trip.
If a cycle fails, e.g. EVAP or SAI, during a subsequent trip but before completion of all necessary
trips, the required number of trips must be restarted.
Porsche 993 Cycle Flag Basics
1. CAT Efficiency - using rear O2 sensors, must drive @ medium load & RPMs < 2500
2. O2 Sensor Aging - monitors O2 sensors' waveform period, must drive @ 2 load ranges,
i.e. light/medium loads
3. SAI - monitors front O2 sensors' minimum voltage, done @ idle or via Short Test
4. Tank Venting - monitors tank vacuum, done @ idle or via Short Test
5. Adaptation - monitors TRAs & FRAs, done @ idle RPM & @ 1500 < RPM < 3000
for 15 seconds @ each RPM (driving not required)
Notes: The above cycle flags when completed (set) comprise one trip. After completion of the
1st trip, the engine is stopped (cycle flags reset) & restarted to begin the 2nd trip, followed by
a 3rd trip if necessary. A cold engine is required between trips for the SAI test if not using the
Short Test. If the engine is stopped, e.g. stalled, before completion of the trip, the trip must be
restarted from the beginning & all completed cycle flags are reset for that trip. Once all the
necessary trips have been completed, the readiness codes will be indicated by an OBDII scanner.
The exception to this is the '98 993, where only one trip is required over numerous days, and the
readiness codes appear as they complete using a generic OBDII scanner.
1. CAT Efficiency - using rear O2 sensors, must drive @ medium load & RPMs < 2500
2. O2 Sensor Aging - monitors O2 sensors' waveform period, must drive @ 2 load ranges,
i.e. light/medium loads
3. SAI - monitors front O2 sensors' minimum voltage, done @ idle or via Short Test
4. Tank Venting - monitors tank vacuum, done @ idle or via Short Test
5. Adaptation - monitors TRAs & FRAs, done @ idle RPM & @ 1500 < RPM < 3000
for 15 seconds @ each RPM (driving not required)
Notes: The above cycle flags when completed (set) comprise one trip. After completion of the
1st trip, the engine is stopped (cycle flags reset) & restarted to begin the 2nd trip, followed by
a 3rd trip if necessary. A cold engine is required between trips for the SAI test if not using the
Short Test. If the engine is stopped, e.g. stalled, before completion of the trip, the trip must be
restarted from the beginning & all completed cycle flags are reset for that trip. Once all the
necessary trips have been completed, the readiness codes will be indicated by an OBDII scanner.
The exception to this is the '98 993, where only one trip is required over numerous days, and the
readiness codes appear as they complete using a generic OBDII scanner.
Last edited by Lorenfb; 03-31-2018 at 01:23 PM.
03-31-2018, 03:38 PM
#13
Rennlist Member
03-31-2018, 04:51 PM
#14
Furthermore, without using a Porsche tester, the engine must be cold before beginning each trip on a '96/'97.
Last edited by Lorenfb; 04-01-2018 at 02:58 PM.
07-02-2020, 05:52 PM
#15
Rennlist Member
Do the readiness codes on the durametric tool show readiness with car running or in ignition position 1? Trying to determine readiness and with engine off they all read “pass”.
Have accomplished the drive cycle 4 times.
Have accomplished the drive cycle 4 times.