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Justin Hebert
Justin Hebert,
Category: Medium and Heavy Trucks
Satisfied Customers: 14
Experience:  Mechanic at Barrett's Truck and Trailer
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Wayne, so I have a 2001 Isuzu frr that I replaced 6 inj.

Customer Question

hi wayne, so I have a 2001 Isuzu frr that I replaced 6 inj. in and turbo. truck is now hard starting and when it starts rpms will not go high and has code 0035
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Justin Hebert replied 1 year ago.
Thanks for using JA. I'm Justin and I will be assisting you today.In order to better assist you I will need a bit more information.What engine do you have in that truck? and what is the vin #?
Customer: replied 1 year ago.
6hk1 and vin is jalf5c13617700876
Customer: replied 1 year ago.
I am having dinner but is it possible to talk on the phone after I complete dinner
Expert:  Justin Hebert replied 1 year ago.
Sure, that can be arranged. I will send you the premium services offer.
Expert:  Justin Hebert replied 1 year ago.
P0035 trouble code definitionP0035 is the code for Turbocharger or Supercharger Bypass Valve Control Circuit High
Expert:  Justin Hebert replied 1 year ago.
What the P0035 code meansIt is necessary to understand that each manufacturer has a slightly different definition for this code as it applies to their particular system. This generally means that there is a problem with the bypass system for the turbocharger or supercharger to relieve pressure either completely or partially, depending on how the system is designed.For this P0035 code, the boost pressure is too high for proper engine operation and power
Expert:  Justin Hebert replied 1 year ago.
What causes the P0035 code?Several things can cause the Check Engine Light to come on and require an OBD-II scanner to indicate this code:Sensor input voltage signals to the engine control module (ECM) indicating a boost level that is more than 14 psi than specified by the manufacturer which will cause a code to be stored and a malfunction indicator lamp to be illuminated. The ECM recognizes this data as an inability to effectively control boost levels.If the boost is more than 14 psi, it can indicate that pressure is not being sent through the bypass valve when it should be in order to relieve pressure.The bypass valve is either stuck shut or not functioning properly.
Expert:  Justin Hebert replied 1 year ago.
What are the symptoms of the P0035 code?The ECM detects the bypass valve control circuit has a high current condition or a short circuit.The ECM cannot control the bypass valve for the turbo or supercharger.The engine may have loss of power.The Check Engine Light will come on once the ECM detects the high current condition.
Expert:  Justin Hebert replied 1 year ago.
How do you diagnose the P0035 code?First verify the code with an OBD-II scanner, then the mechanic should reset the code and road test the vehicle to determine if the Check Engine Light comes back on and if the P0035 code returns.Depending on the manufacturer, a boost pressure gauge test will need to be determined to see if the boost pressure is within the manufacturer's recommended range.If the pressure is too high, an inspection of the bypass valve and a pressure test must be done. Some bypass valves are spring operated and others, especially Asian models, are diaphragm operated with an electric sensor and control system.
Expert:  Justin Hebert replied 1 year ago.
Common mistakes when diagnosing the P0035 codeThe most common mistakes on this code are related to not following test procedure and assuming basic components are operating normally.Often a pressure sensor on the intake may be faulty and indicates high pressure sent to the ECM.Do not replace the bypass valve, turbocharger, or supercharger unless it is clearly at fault.
Expert:  Justin Hebert replied 1 year ago.
How serious is the P0035 code?This code requires absolutely immediate attention and should be diagnosed as soon as possible. The vehicle will still run but serious damage can occur to the engine if the problem is not repaired, and if the pressure is too high engine damage due to a too lean fuel mixture may occur.Often times, if the Check Engine Light came on immediately at start up, the OBD- II system can be reset and the vehicle will operate normally.
Expert:  Justin Hebert replied 1 year ago.
What repairs can fix the P0035 code?The most common repairs to address the P0035 code are as follows:Verify the code with an OBD-II scanner, reset the fault codes, and perform a road test.If the P0035 code returns, then follow the test procedure:Do a pressure test on the intake system between the turbocharger and intake throttle valve. This will verify if the pressure is too high as specified by the manufacturer.If the pressure is too high, check the bypass valve to determine if it is slightly or completely closed which will allow boost pressure to build excessively. This may require changing the bypass valve or the actuator with diaphragm.If the pressure test is in the normal range as specified by the manufacturer, the pressure sensor may be faulty.Having had this code before, it has been generally a problem with the bypass valve or waste gate stuck shut. If it is a spring loaded type, exhaust debris sticks the valve so it cannot open when the pressure increases beyond the specified maximum boost. If it is the diaphragm type, the diaphragm fails on the pressure operated servo and can be replaced separately from the turbo charger unit.This problem is not normally a problem with the turbocharger itself. Newer cars emission systems recycle heavy carbon and oil mist from the crankcase directly into the intake and some bypass valves get clogged up similar to modern intake manifolds.
Expert:  Justin Hebert replied 1 year ago.
Hopefully that information is helpful. If you have any further questions, feel free to ask. and don't worry, you can still ask a question even after providing a rating.
Expert:  Justin Hebert replied 1 year ago.
Do you need further assistance?
Expert:  Justin Hebert replied 1 year ago.
Please be sure to submit a rating as that is the only way I get paid. If you have further questions, or need more information you can still post a reply even after rating. Thank you.

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