For a while I have been having codes related to inlet and exhaust CPSs so I decided to change 'em once and for all.
However the following codes prevailed as they have been lingering around before the CPS replacement, although the order could be a bit different aside from the common start 8F: E-Box Fan
The newest reading shows the following:-
8F E-box-fan
AA secondary air system, flow too slow
0B Exhaust camshaft pos. sensor, cyl. 5-8
A2 crankshaft/camshalf pos. correlation, cyl. 5-8
D1, D3, D5 Misfiring during warm-up, Cyl 5, 7, multiple
I have replaced my MAFS at about 45,000 km (the car currently registers about 92,000 km) and it was running great for a few years until recently when it hesitates on WOT acceleration [uphill, from 2nd to 3rd]. The only other problem is the occasional inaccuracy in ambient temp readings at the start of the car that is self-corrected after a few minutes (-3 deg C in Hong Kong? ), probably due to a less than perfect IATS kit installation a couple of years back.
Pardon this, but I'm going to ask the obvious question first: did you reset (clear) the error codes after changing the CPS's? If you want to rule out the MAFS do member DavidS's test and look for ~130+ L/h.
For a while I have been having codes related to inlet and exhaust CPSs so I decided to change 'em once and for all.
However the following codes prevailed as they have been lingering around before the CPS replacement, although the order could be a bit different aside from the common start 8F: E-Box Fan
The newest reading shows the following:-
8F E-box-fan
AA secondary air system, flow too slow
0B Exhaust camshaft pos. sensor, cyl. 5-8
A2 crankshaft/camshalf pos. correlation, cyl. 5-8
D1, D3, D5 Misfiring during warm-up, Cyl 5, 7, multiple
I have replaced my MAFS at about 45,000 km (the car currently registers about 92,000 km) and it was running great for a few years until recently when it hesitates on WOT acceleration [uphill, from 2nd to 3rd]. The only other problem is the occasional inaccuracy in ambient temp readings at the start of the car that is self-corrected after a few minutes (-3 deg C in Hong Kong? ), probably due to a less than perfect IATS kit installation a couple of years back.
Any advice for me/my indy would be appreciated.
AA = Carbon Buildup. Get a Powerchip or go pay the dealer $5K to make it go away for a couple years. This code is completely unrelated to the CPS.
0B = You changed all 4 of your sensors? If so, then your next step is to change your driver's side solenoid, as the DME is getting a reading back telling it that the VANOS is not in the position the DME asked for.
A2 = This could be related to the above solenoid issue or could indicate a need for a new crankshaft position sensor. If you recently had clutch work it could also imply that the re-installation / adjustment process was improperly performed.
D1, D3, D5 = You need new plugs or new plasma boots. Start with plugs since they are cheaper
Pardon this, but I'm going to ask the obvious question first: did you reset (clear) the error codes after changing the CPS's? If you want to rule out the MAFS do member DavidS's test and look for ~130+ L/h.
Thanks for the reminder, I did routinely re-set the code reader every time after pulling the codes so that part is clear. I would conduct the MAFS test sometime following David's routine just to make sure though.
AA = Carbon Buildup. Get a Powerchip or go pay the dealer $5K to make it go away for a couple years. This code is completely unrelated to the CPS.
0B = You changed all 4 of your sensors? If so, then your next step is to change your driver's side solenoid, as the DME is getting a reading back telling it that the VANOS is not in the position the DME asked for.
A2 = This could be related to the above solenoid issue or could indicate a need for a new crankshaft position sensor. If you recently had clutch work it could also imply that the re-installation / adjustment process was improperly performed.
D1, D3, D5 = You need new plugs or new plasma boots. Start with plugs since they are cheaper
d-
Many thanks for the timely advice as I am bringing my car for service today. Except for the CBU issue (the AA code has only appeared for about 6 months) your analysis relieves me as the problems, if eventually aggravated, can still be dealt with by replacing one or two wear-and-tear parts. The plugs were replaced 25,000 km (~ 15k miles) back and I need to double check the CPSs. In fact 3 of them were replaced in Jan while the 4th one (Bank 1 inlet CPS) was replaced 40,000 km (25k miles) back.
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1) the AA code appears in the absence of other codes
2) the AA code re-appears frequently
In my experience (both cars), the AA code is frequently a collateral code that trips when start up conditions are not normal. I have frequently seen the AA code 'bundled' with cps related codes. When I deal with the cps-related codes, the AA code magically disappears and doesn't come back.
The AA code trips when the ECU is not seeing the expected low voltage signal from the pre-cat O2 sensor during open loop (cold) start up. The ECU is expecting a low voltage signal due to the air being pumped into the exhaust. If the signal is above spec, a code is set. Presumably factors that can richen the mixture during start up can set an AA code. For example, if you have cold start misfires (which you seem to have), this could create a richer mixture than the ECU is expecting.
In my experience (both cars), the AA code is frequently a collateral code that trips when start up conditions are not normal. I have frequently seen the AA code 'bundled' with cps related codes. When I deal with the cps-related codes, the AA code magically disappears and doesn't come back.
The AA code trips when the ECU is not seeing the expected low voltage signal from the pre-cat O2 sensor during open loop (cold) start up. The ECU is expecting a low voltage signal due to the air being pumped into the exhaust. If the signal is above spec, a code is set. Presumably factors that can richen the mixture during start up can set an AA code. For example, if you have cold start misfires (which you seem to have), this could create a richer mixture than the ECU is expecting.
Dave
Many thanks Dave for responding to my situation even after having written extensively on the issue of CBU which I read with interest and respect. As my car is a European version I did not have the trigger for the SES alarm regardless of the actual carbon build up issue so I do not have to attend to root cause of the AA code as a matter of urgency.
Interestingly the indy diagnosis still points toward a Bank 2 exhaust CPS problem so I am 'borrowing' one to check if my last replacement work in January '09 was not done properly. The AA code did first appear with only the CPS codes though without the cold-start misfires. Will revert with my finding in time when I eventually identify the cause (and fix it hopefully). Thanks again.
The AA code did first appear with only the CPS codes though without the cold-start misfires. Will revert with my finding in time when I eventually identify the cause (and fix it hopefully). Thanks again.
I've observed AA bundled with cps-related in the absence of misfires on both my cars. It will be interesting to see another data point on this...when you cure the cps code(s), do the AA codes disappear also. Look forward to an update.
4Likes
), probably due to a less than perfect IATS kit installation a couple of years back. 
Linear Mode
