2001 Lexus IS300 Multiple Codes, four months of headaches, and consistent cop problem
Thread Starter
2nd gear
Joined: May 2024
Posts: 2
Likes: 0
From: AZ
2001 Lexus IS300 Multiple Codes, four months of headaches, and consistent cop problem
Just over 4 months ago, my 01 Lexus IS300 was driving very sluggish but no codes for over a month, then finally, P0500-VSS- Speed Sensor #1 or #2 I honestly don't remember, it's been so long.. I replaced both, right after my darn car wouldn't go over 3,200-3,800ish RPMS.. Then finally just died on me.. And finally two days ago I got it running once I cut the positive wire to the fuel pump (there is a lot more to it than that, but don't want to type it).. replaced fuel pump & regulator (w/ used ones).. threw three codes finally... P0172, P0303, an P0110.. Replaced the MAF, changed nothing, actually made it worse, engine died around 2000 RPMS.. I'm pretty sure the exhaust is leaking where the two heads connect to one, someone please help me.. Jourdain Wood- 602-319-8270
Lead Lap
Joined: Nov 2019
Posts: 3,693
Likes: 1,102
From: Michigan
Hello,
With not much written out, expect a lot of repetition.
How did the issue first begin?
Were there any modifications done to the car at all?
If the car starts and at least somewhat runs, try connecting the OBD2 scan tool and monitoring the Engine Live Data, specifically Long Term Fuel Trims, Short Term Fuel Trims, MAF readouts and Ignition Timing. To see if the sensors may be playing a part in this issue, try disconnecting MAF and each of the A/F sensors one-by-one to see what changes, if one of them feeds erroneous information to the ECU.
P0172 - System Too Rich, that's a pretty unique fault code, in fact it's about the first time I see it, as there isn't much usually that can cause the engine to run Rich, makes it even more interesting to see Live Data. Here is a very detailed explanation of what Fuel Trims are, and what they determine, including the causes for Rich condition. In short, it can only be caused by damaged Injectors (very unlikely for all of them to fail), excessive Fuel Pressure, or an A/F sensor damaged beyond all recognition.
Hope this helps and best of luck!
With not much written out, expect a lot of repetition.
How did the issue first begin?
Were there any modifications done to the car at all?
If the car starts and at least somewhat runs, try connecting the OBD2 scan tool and monitoring the Engine Live Data, specifically Long Term Fuel Trims, Short Term Fuel Trims, MAF readouts and Ignition Timing. To see if the sensors may be playing a part in this issue, try disconnecting MAF and each of the A/F sensors one-by-one to see what changes, if one of them feeds erroneous information to the ECU.
P0172 - System Too Rich, that's a pretty unique fault code, in fact it's about the first time I see it, as there isn't much usually that can cause the engine to run Rich, makes it even more interesting to see Live Data. Here is a very detailed explanation of what Fuel Trims are, and what they determine, including the causes for Rich condition. In short, it can only be caused by damaged Injectors (very unlikely for all of them to fail), excessive Fuel Pressure, or an A/F sensor damaged beyond all recognition.
Hope this helps and best of luck!