Pull codes P0172/P0175, need help diagnoising
09-06-14, 06:45 AM
#17
Yesterday I had both of these codes (p0173 p0175) pop up on my ISF, had a unmetered air leak after the MAF, ( and did a lil cleaning of the MAF sensor ) and a reset of the ECU, drove the car for like 15 or 20 miles (CEL lights was still on after the ECU reset) and next restart, they all went off , no more CEL
11-02-15, 09:54 PM
#18
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This codes appeared on the scanner. P0172 and P0175.
OK, so, after searching for info, first I cleaned the MAF sensor with a MAF cleaner.
I also changed the spark plugs. Still have the codes and have very high HC levels (and high CO)
Then, bought new and replaced the old A/F sensors of both banks.
They work perfect and the HC levels at high rpms really improved but still have high HC levels at idle. And the codes also reappeared.
What else to do guys? Any ideas
OK, so, after searching for info, first I cleaned the MAF sensor with a MAF cleaner.
I also changed the spark plugs. Still have the codes and have very high HC levels (and high CO)
Then, bought new and replaced the old A/F sensors of both banks.
They work perfect and the HC levels at high rpms really improved but still have high HC levels at idle. And the codes also reappeared.
What else to do guys? Any ideas
11-03-15, 02:01 PM
#20
Super Moderator
I thought P0172 and P0175 are from the front oxygen sensors, the ones upstream of the cats.
12-20-15, 03:47 PM
#22
Super Moderator
12-22-15, 11:40 PM
#23
This codes appeared on the scanner. P0172 and P0175.
OK, so, after searching for info, first I cleaned the MAF sensor with a MAF cleaner.
I also changed the spark plugs. Still have the codes and have very high HC levels (and high CO)
Then, bought new and replaced the old A/F sensors of both banks.
They work perfect and the HC levels at high rpms really improved but still have high HC levels at idle. And the codes also reappeared.
What else to do guys? Any ideas
OK, so, after searching for info, first I cleaned the MAF sensor with a MAF cleaner.
I also changed the spark plugs. Still have the codes and have very high HC levels (and high CO)
Then, bought new and replaced the old A/F sensors of both banks.
They work perfect and the HC levels at high rpms really improved but still have high HC levels at idle. And the codes also reappeared.
What else to do guys? Any ideas
Did your codes first appear after having the ELF recall done?
12-25-15, 10:29 AM
#25
As I was driving home from work yesterday and my dashboard lit up like a Christmas tree... went to my local performance shop to get the codes checked out and i got the same ones the OP got (P0172 and P0175)
The car drives a little funny and feels like it bogs out at low RPM's and easy throttle but at WOT it acts perfectly normal. Another thing I have noticed is that the tranny shifts really hard, not sure if that is related to the car wanting to bog out at low rpm.
I do have an after market intake but I have never had issues with it in the past.
Any suggestions? I'm going to start off with re installing my stock intake and disconnecting the battery for a couple of minutes.
The car drives a little funny and feels like it bogs out at low RPM's and easy throttle but at WOT it acts perfectly normal. Another thing I have noticed is that the tranny shifts really hard, not sure if that is related to the car wanting to bog out at low rpm.
I do have an after market intake but I have never had issues with it in the past.
Any suggestions? I'm going to start off with re installing my stock intake and disconnecting the battery for a couple of minutes.
01-08-16, 09:46 PM
#26
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I pulled up the code on the repair manual, you may try looking into the trouble areas, as it could be the a/f or o2 sensors, but hopefully some of this helps:
Last Modified: 6-26-2013 6.4 C Doc ID: RM000000WC300HX
Model Year: 2006 Model: IS350 Prod Date Range: [08/2005 - ]
Title: 2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0171,P0172,P0174,P0175; System Too Lean (Bank 1); 2006 MY IS350 [08/2005 - ]
DTC
P0171
System Too Lean (Bank 1)
DTC
P0172
System Too Rich (Bank 1)
DTC
P0174
System Too Lean (Bank 2)
DTC
P0175
System Too Rich (Bank 2)
DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the short-term and the long-term fuel trim.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.
I work at the dealer and am a CL member, would you be able to trust me? heh.
Last Modified: 6-26-2013 6.4 C Doc ID: RM000000WC300HX
Model Year: 2006 Model: IS350 Prod Date Range: [08/2005 - ]
Title: 2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0171,P0172,P0174,P0175; System Too Lean (Bank 1); 2006 MY IS350 [08/2005 - ]
DTC
P0171
System Too Lean (Bank 1)
DTC
P0172
System Too Rich (Bank 1)
DTC
P0174
System Too Lean (Bank 2)
DTC
P0175
System Too Rich (Bank 2)
DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the short-term and the long-term fuel trim.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.
I work at the dealer and am a CL member, would you be able to trust me? heh.
I will replace the MAF sensor and see if the codes come back.
01-13-17, 04:35 PM
#27
Driver School Candidate
I pulled up the code on the repair manual, you may try looking into the trouble areas, as it could be the a/f or o2 sensors, but hopefully some of this helps:
Last Modified: 6-26-2013 6.4 C Doc ID: RM000000WC300HX
Model Year: 2006 Model: IS350 Prod Date Range: [08/2005 - ]
Title: 2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0171,P0172,P0174,P0175; System Too Lean (Bank 1); 2006 MY IS350 [08/2005 - ]
DTC
P0171
System Too Lean (Bank 1)
DTC
P0172
System Too Rich (Bank 1)
DTC
P0174
System Too Lean (Bank 2)
DTC
P0175
System Too Rich (Bank 2)
DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the short-term and the long-term fuel trim.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.
I work at the dealer and am a CL member, would you be able to trust me? heh.
Last Modified: 6-26-2013 6.4 C Doc ID: RM000000WC300HX
Model Year: 2006 Model: IS350 Prod Date Range: [08/2005 - ]
Title: 2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0171,P0172,P0174,P0175; System Too Lean (Bank 1); 2006 MY IS350 [08/2005 - ]
DTC
P0171
System Too Lean (Bank 1)
DTC
P0172
System Too Rich (Bank 1)
DTC
P0174
System Too Lean (Bank 2)
DTC
P0175
System Too Rich (Bank 2)
DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the short-term and the long-term fuel trim.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.
I work at the dealer and am a CL member, would you be able to trust me? heh.
01-14-17, 05:12 PM
#28
Instructor
100% sure it's the aftermarket intake , gas and engine oil , p0174 system too lean or p0175 running rich , put F Sport intake on any aftermarket intake cheap or expensive will give u this code also you might have vacuum hose leaks this also gives 0174 0175
10-16-19, 10:09 AM
#29
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2006 Lexus IS350 had its fuel rail and air bag recall work done yesterday. Today, My check engine light came on along with the track off light. The P0172 code came up. I went to lexus and they say its nothing to do with the recall work they did on the car. I will be out of the country for 3 weeks and gonna come back to them with this.
11-24-19, 01:26 AM
#30
Bumping an old thread. Added an extra quart to my 06 IS250 (was a bit low before an oil change) and I got these codes after driving probably 50 miles. It isn't overfilled. Any ideas?
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