ES300 stutters. CEL code P0171. Need advice
#1
Lead Lap
Thread Starter
ES300 stutters. CEL code P0171. Need advice
Help. I bought a 99 ES300 last Jan. Now the check engine light is on. Also the vsc and vsc off are on. AutoZone found the following codes: P0171 and P1133. Both indicate some sort of malfunction at bank 1 sensor 1. Additionally when I'm cruising along with my foot lightly on the accelerator the car stutters.
I cleaned the MAF sensor. It was dirty. After cleaning the MAF sensor the stuttering was more pronounced and frequent.
I'm thinking I need to replace the O2 sensor. I've read other threads with P0170 error code but none with stuttering. Any advice would be appreciated. Thanks in advance Tom
I cleaned the MAF sensor. It was dirty. After cleaning the MAF sensor the stuttering was more pronounced and frequent.
I'm thinking I need to replace the O2 sensor. I've read other threads with P0170 error code but none with stuttering. Any advice would be appreciated. Thanks in advance Tom
#2
Lexus Test Driver
iTrader: (5)
Help. I bought a 99 ES300 last Jan. Now the check engine light is on. Also the vsc and vsc off are on. AutoZone found the following codes: P0171 and P1133. Both indicate some sort of malfunction at bank 1 sensor 1. Additionally when I'm cruising along with my foot lightly on the accelerator the car stutters.
I cleaned the MAF sensor. It was dirty. After cleaning the MAF sensor the stuttering was more pronounced and frequent.
I'm thinking I need to replace the O2 sensor. I've read other threads with P0170 error code but none with stuttering. Any advice would be appreciated. Thanks in advance Tom
I cleaned the MAF sensor. It was dirty. After cleaning the MAF sensor the stuttering was more pronounced and frequent.
I'm thinking I need to replace the O2 sensor. I've read other threads with P0170 error code but none with stuttering. Any advice would be appreciated. Thanks in advance Tom
#4
Lexus Test Driver
iTrader: (5)
P0171 is a MAF sensor issue. Do you have an aftermarket intake system or wet type filter system (K&N)? I was told the wet type intake system wreck havoc on our MAF sensors. I would recommend cleaning it and reset your ECU. I had the same issue and cleaned it several times, so now I just recently bought a new MAF sensor, so far so good.
#5
P0171 is a MAF sensor issue. Do you have an aftermarket intake system or wet type filter system (K&N)? I was told the wet type intake system wreck havoc on our MAF sensors. I would recommend cleaning it and reset your ECU. I had the same issue and cleaned it several times, so now I just recently bought a new MAF sensor, so far so good.
i did mess with the throttle position cable too
pic of pcv valve location and 4ga upgraded ground wire
Last edited by dcapo; 11-06-10 at 09:34 PM. Reason: added pic
#6
Lead Lap
Thread Starter
Stuttering/Jerking/bucking stopped but VSC lights still come on
I've been trying to troubleshoot my car's problem. Things I tried are: Cleaning the MAS, adding fuel injector cleaner, and searching for vacuum line leaks. Finally the Stuttering/Jerking/bucking got so bad I broke down and replaced the MAS.
It's been 3 days and no Stuttering/Jerking/bucking but I still get the VSC and VSC OFF lights periodically, usually after about 3 or 4 minutes driving from a cold start. I'm wondering if this might be an indication of a failing air/fuel sensor. I read somewhere that unheated O2 sensors take several minutes to warm up before being they will generate a voltage signal. During his warm up phase, the fuel feedback control system remains in "open loop" and does not use the O2 sensor signal to adjust the fuel mixture. Could it be that once the sensor is warmed up it generates faulty signals leading to the error lights and the Stuttering/Jerking/bucking? Anyone have any thoughts on this theory.
Before replacing the MAS, the VSC and the VSC off lights would come on after 3 or 4 minutes. Then the check engine light (CEL) would come and the Stuttering/Jerking/bucking would start.
I have a OBD II scanner due tomorrow that should help me diagnosis this problem.
I'm not convinced I've solved the Stuttering/Jerking/bucking problem because its' only been three days.
Thanks in advance for your advice and input. Tom
It's been 3 days and no Stuttering/Jerking/bucking but I still get the VSC and VSC OFF lights periodically, usually after about 3 or 4 minutes driving from a cold start. I'm wondering if this might be an indication of a failing air/fuel sensor. I read somewhere that unheated O2 sensors take several minutes to warm up before being they will generate a voltage signal. During his warm up phase, the fuel feedback control system remains in "open loop" and does not use the O2 sensor signal to adjust the fuel mixture. Could it be that once the sensor is warmed up it generates faulty signals leading to the error lights and the Stuttering/Jerking/bucking? Anyone have any thoughts on this theory.
Before replacing the MAS, the VSC and the VSC off lights would come on after 3 or 4 minutes. Then the check engine light (CEL) would come and the Stuttering/Jerking/bucking would start.
I have a OBD II scanner due tomorrow that should help me diagnosis this problem.
I'm not convinced I've solved the Stuttering/Jerking/bucking problem because its' only been three days.
Thanks in advance for your advice and input. Tom
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#8
Lead Lap
Thread Starter
It's been a week since I've replaced the MAF sensor. No stuttering since replacing it. Four days since I've seen the VSC and VSC off lights. It's looking more likely the problem was the MAF sensor. I'll report back if I get any more error lights. Thanks Tom
Last edited by tomf; 11-16-10 at 06:25 AM. Reason: spelling
#9
Lead Lap
Thread Starter
VSC lights and DTC codes are back
Yesterday the VSC, VSC OFF and CEL returned. I used by new OBD II scanner and got the same codes; P1133 and P0171. Also read the freeze fame data:
SHRTF1(%) 19.5
LONGFT1(%) 24.2
SHRTFT2(%) 10.9
LONGFT2(%) 3.1
So today I'm replacing my Air and Fuel Ratio Sensor with a Denso 234-9007.
I'm just waiting for UPS to deliver it so I can install it. I've attached a picture of the old air and fuel sensor.
SHRTF1(%) 19.5
LONGFT1(%) 24.2
SHRTFT2(%) 10.9
LONGFT2(%) 3.1
So today I'm replacing my Air and Fuel Ratio Sensor with a Denso 234-9007.
I'm just waiting for UPS to deliver it so I can install it. I've attached a picture of the old air and fuel sensor.
#11
Lead Lap
Thread Starter
See post #8. Replaced it about a week ago. I thought my problem was fixed until yesterday.
#12
Lead Lap
Thread Starter
It's been 2.5 weeks since I've changed the air fuel ratio sensor. No more stuttering. The VSC and VSC off lights came on twice which went away the next time I started the engine. Once I read the OBD II data which indicated a pending problem with the downstream oxygen sensor (P0136, if I remember correctly). Looks like eventually I'll have to replace the downstream O2 sensor. I'll wait until the check engine like comes on and stays on.
It appears my initial problem (P0171) was with the bank 1, sensor 1 air fuel ratio sensor. I'll update if any related problems appear.
It appears my initial problem (P0171) was with the bank 1, sensor 1 air fuel ratio sensor. I'll update if any related problems appear.
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