My 2005 base model C6 which I've had for 18 months now , has been running fine , however I moved to South East Spain last year, and you only have to look at the car after cleaning it to see it covered in a fine dust again . As such i thought I'd carry out a bit of preventative maintenance and clean the Throttle body and MAF sensor using the appropriate cleaners for each , removing both from the car and without moving the TB butterfly . Nice easy job ,had it done and dusted (sic) and all back together within an hour ...however , I took the car out for a run and all seemed good at first , a 5 minute drive to the motorway and then a good 40k of clear road to give it a blast , however coming off the motorway , and to a quick stop, the car went into "Reduced Power Mode ". Once the car has been switched off and left for a minute or two its starts again fine , but on slow roads it soon drops back to "Reduced Engine Power " .I've tried a "relearn ", which id seen on a different forum ...ie 3 min idle , off for 1 min, another 3 min idle a couple of times and I'm still suffering the same issue ...Good at speed on the Motorway but drops into "REP" mode when it slows . As said , everything was fine before I did the clean .. Any ideas anyone ? Thanks
Throttle body / MAF issues !
- Thread starter Museo
- Start date
teamzr1
Supporting vendor
What products did you use to clean the MAF and TB ?
Did you use a MAF cleaner product and not over spray the very thin exposed sensor wires or break them
Disconnect the connector from the MAF and check to make sure neither the wiring pins nor MAF pins did not get bent
or pushed inwards and make sure when connecting the connector again that fully seated to the MAF
Did you take the MAF off, if so make sure the airflow arrow is pointing to the TB as if on backwards would cause problems
Closely look that the airbridge from the aircleaner, to the TB is on correctly, look at the bottom side to make sure
the rubber couplers did not get rolled over and is causing unmetered airflow which would confuse the PCM
Any error codes showing on the DIC ?
Looking at my C5 notice how the MAF is positioned
Did you use a MAF cleaner product and not over spray the very thin exposed sensor wires or break them
Disconnect the connector from the MAF and check to make sure neither the wiring pins nor MAF pins did not get bent
or pushed inwards and make sure when connecting the connector again that fully seated to the MAF
Did you take the MAF off, if so make sure the airflow arrow is pointing to the TB as if on backwards would cause problems
Closely look that the airbridge from the aircleaner, to the TB is on correctly, look at the bottom side to make sure
the rubber couplers did not get rolled over and is causing unmetered airflow which would confuse the PCM
Any error codes showing on the DIC ?
Looking at my C5 notice how the MAF is positioned
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Hi TeamZR1...
I used "Liqui Moly " air flow sensor cleaner on the MAF and "Motul" Throttle Body Cleaner on the TB...both are undamaged and the MAF is facing the correct way. All pins and connections are in good order and the car was running fine before hand ( I know ...if it aint broke , dont fix it )...No Codes showing on the DIC either !!!
I used "Liqui Moly " air flow sensor cleaner on the MAF and "Motul" Throttle Body Cleaner on the TB...both are undamaged and the MAF is facing the correct way. All pins and connections are in good order and the car was running fine before hand ( I know ...if it aint broke , dont fix it )...No Codes showing on the DIC either !!!
teamzr1
Supporting vendor
IF no DTCs are tripping, then I agree,
Have to check very closely for an unmetered air leak from aircleaner to coupler attached to the TB
As I mentioned, the rubber coupler to TB tends to fold over at the bottom and pulls in unmetered air
Did not take the TB off during cleaning or disconnected the wiring connectors off the TPS or the drive by wire ?
I did take the TB off and disconnected the wiring …
teamzr1
Supporting vendor
No real reason to take TB for cleaning as simple spray cleaner would do fine
Check those wiring connectors as to any bent PIDs
Possible the vacuum hoses that go to TB not fully connected?
TRY these :
Perform the following procedure to return the TPS to the correct position:
Sync TPS to PCM
With ign key off, unplug wiring connector from TPS
Turn ign key on but engine OFF
Wait a few seconds, could trip a TPS DTC
Turn key off, connect TPS wiring connector
Start engine and if need be clear DTC
Idle relearns
Automatic Transmission:
1 Turn off the ignition
2 Restore the PCM battery (if was disconnected)
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Start the engine
6 Allow the engine coolant temperature to reach 176 degrees F
7 Shift the transmission selector into the drive range
8 Allow the engine to idle for 5 minutes
9 Turn on the AC controls (Omit for 2000-02 model)
10 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
11 Shift the transmission selector into Park
12 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
13 Turn off the AC controls (Omit for 2000-02 model)
14 Allow the engine to idle for 5 minutes
15 Turn off the engine for 15 seconds
Manual Transmission:
1 Turn Off the ignition
2 Restore the PCM battery feed
3 Turn Off the AC controls
4 Set the parking brake and block the drive wheels
5 Transmission in neutral
6 Start the engine
7 Allow the engine coolant temperature to reach 176 degrees F
8 Turn on the AC controls (Omit for 2000-02 model)
9 Allow the engine to idle for 5 minutes (Omit for 2000-02 model)
10 Turn off the AC controls (Omit for 2000-02 model)
11 Allow the engine to idle for 5 minutes
12 Turn off the engine for 15 seconds
Well I finally was able to have another go at it ! ...stripped it back down again , checked on the wires on the MAF , airflow direction etc , and everything looks good ...checked for air coming in elsewhere and cant see anything obvious ...checked the coupler and that looks fine ...both connections on the MAF and TB look fine .
So put it all back together and went for a run ....still getting the same issue . Fine at speed on the motorway but as soon as iI came off and came to a stop it went into reduced power mode ...except now I'm getting a P1516 & P2101 codes ...
I'm going to try cleaning the TB electrical connection and see if that makes a difference as I disconnected the MAF connection last year when I changed the rad and that didn't cause any issues ...and I'll try the re learn and see if that makes a difference !
So put it all back together and went for a run ....still getting the same issue . Fine at speed on the motorway but as soon as iI came off and came to a stop it went into reduced power mode ...except now I'm getting a P1516 & P2101 codes ...
I'm going to try cleaning the TB electrical connection and see if that makes a difference as I disconnected the MAF connection last year when I changed the rad and that didn't cause any issues ...and I'll try the re learn and see if that makes a difference !
teamzr1
Supporting vendor
Both DTCs point to the drive by wire either at the TB on left side or the APP which is control at gas pedal
Check pins of connector to the TB on driver side as clean and no male or female pins bent ?
Need to do the relearns
another reason people should own and use a OBD2 scanner and let the PCM tell you what is functioning out of its normal operating window
P1516
Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
P2101
Throttle Actuator "A" Control Motor Circuit Range/Performance
Did you check to make sure no vacuum leaks to the hose that connect to the TB
1 is for EVAP on drivers side and PCV which connects to TB on right side
The throttle actuator is a critical component of the electronic throttle control system, which is responsible for controlling the throttle valve opening and closing.
The throttle actuator is controlled by the Engine Control Module (ECM) and is typically a DC motor that operates within a specific range of values.
When the ECM detects a problem with the throttle actuator control motor circuit, it will set the P2101 code. This code indicates that the ECM has detected a range or performance problem with the throttle actuator control motor circuit, which can cause issues with the engine's performance, including poor idle, hesitation, and lack of power.
Check pins of connector to the TB on driver side as clean and no male or female pins bent ?
Need to do the relearns
another reason people should own and use a OBD2 scanner and let the PCM tell you what is functioning out of its normal operating window
P1516
Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
P2101
Throttle Actuator "A" Control Motor Circuit Range/Performance
Did you check to make sure no vacuum leaks to the hose that connect to the TB
1 is for EVAP on drivers side and PCV which connects to TB on right side
Detailed Description of Error P2101
OBDII error code P2101 is a generic trouble code that indicates a problem with the Throttle Actuator ''A'' Control Motor Circuit Range/Performance.The throttle actuator is a critical component of the electronic throttle control system, which is responsible for controlling the throttle valve opening and closing.
The throttle actuator is controlled by the Engine Control Module (ECM) and is typically a DC motor that operates within a specific range of values.
When the ECM detects a problem with the throttle actuator control motor circuit, it will set the P2101 code. This code indicates that the ECM has detected a range or performance problem with the throttle actuator control motor circuit, which can cause issues with the engine's performance, including poor idle, hesitation, and lack of power.
Possible Causes of Error P2101
There are several possible causes of the P2101 error code, including:- Faulty throttle actuator
- Faulty throttle position sensor
- Faulty Engine Control Module (ECM)
- Short circuit or open circuit in the throttle actuator control motor circuit
- Poor connection or corrosion in the throttle actuator control motor circuit
- Incorrect throttle actuator calibration
- Vacuum leaks or intake leaks
- Faulty throttle body
Possible Fixes for Error P2101
To fix the P2101 error code, you may need to perform the following steps:- Inspect the throttle actuator control motor circuit for any signs of damage or corrosion
- Check the throttle actuator for proper operation and calibration
- Check the throttle position sensor for proper operation and calibration
- Check the ECM for any software updates or issues
- Perform a throttle body cleaning or replacement if necessary
- Check for vacuum leaks or intake leaks and repair if necessary
teamzr1
Supporting vendor
The reason PCM goes into limp mode is safety since using drive by wire
There are multi cross-checks to assure DBW is not gone wacko and is commanding APP (controls on gas pedal and motor on TB)
to go faster and causing crashes
As example and again why a OBD2 scanner helps debug problems is
Say at idle the TPS is reporting the angle of butterfly in TB is 10% open,
but the APP is saying the gas pedal is down 12 % but the MAF is reporting 2 lbs/min airflow
The PCM calibration looks at those values and compares it to that calibration and if all this does not match
correctly the PC is going to trip into limp mode for safety reasons
There are multi cross-checks to assure DBW is not gone wacko and is commanding APP (controls on gas pedal and motor on TB)
to go faster and causing crashes
As example and again why a OBD2 scanner helps debug problems is
Say at idle the TPS is reporting the angle of butterfly in TB is 10% open,
but the APP is saying the gas pedal is down 12 % but the MAF is reporting 2 lbs/min airflow
The PCM calibration looks at those values and compares it to that calibration and if all this does not match
correctly the PC is going to trip into limp mode for safety reasons
FelixP
Busy user
I had this with my 2005 the day after I got it. Cleaning the connector on the throttle body sorted it out. Are the pins in good condition? Does it come up if you wiggle the wiring by the throttle body? With your OBD scanner can you clear the faults and the car behave as normal again?
Hi Felix .
Sorry for the delay in getting back to you .
I’ve cleaned the pins and plug and applied a dielectric grease but that hasn’t sorted it …Pins and plug are in good order for what it’s worth .
I’m just getting the P1516 code now but when I clear it , it still comes back and the car still drops into Reduced Engine Power mode FFS !!!
Sorry for the delay in getting back to you .
I’ve cleaned the pins and plug and applied a dielectric grease but that hasn’t sorted it …Pins and plug are in good order for what it’s worth .
I’m just getting the P1516 code now but when I clear it , it still comes back and the car still drops into Reduced Engine Power mode FFS !!!
FelixP
Busy user
How are the wires underneath the loom? Peel it back they may be a bit hard and brittle after sitting in the engine bay for 20yrs. Perhaps there's a break inside which happened when you disconnected it and moved them
Good point …That’ll be the next job !! I tried a idle reset but that hasn’t helped ..
Thanks
