slipping
Full Access Member
Mine was sputtering, RPMs fluctuating all crazy, sounded maybe like it backfired then died. Tried to start and dies right back. Got at least half tank gas. Maybe fuel pump?
What did you do to your OBS GMT400 Tahoe/Yukon Today?
- Thread starter 96ProCompTahoe
- Start date
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SunlitComet
OBS Jedi-Do Good
maybe if it start to run and then stalls out the fuel pressure might have drop around 30 psi or so. actually it more flow rate when it breaks like that.
and riley if it is just moisture evacuate it for at least two hours replace the drier and evacuate it again to get all of it out.before recharging it may just get you by for a long while. if it shows acid in the system then flushing is needed and will cost more.
and riley if it is just moisture evacuate it for at least two hours replace the drier and evacuate it again to get all of it out.before recharging it may just get you by for a long while. if it shows acid in the system then flushing is needed and will cost more.
SunlitComet
OBS Jedi-Do Good
slipping
Full Access Member
Starts right up. Read a thread on CPS and that was exactly what it was doing.
slipping
Full Access Member
Alright I'll go check my codes in minute
---------- Post added at 08:21 PM ---------- Previous post was at 07:53 PM ----------
codes P0155 and P0300
---------- Post added at 08:21 PM ---------- Previous post was at 07:53 PM ----------
codes P0155 and P0300
SunlitComet
OBS Jedi-Do Good
P0155
Circuit Description
The Heated Oxygen Sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The Control Module (PCM/VCM) supplies the HO2S with signal High and Low circuits. Ignition voltage and ground is supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.
The HO2S contains a heater that is necessary in order to quickly warm the sensor to operating temperature and maintain the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. Once the HO2S has reached operating temperature, the Control Module monitors the HO2S bias, or reference, voltage as well as the HO2S signal voltage for closed loop fuel control. During normal Closed Loop fuel control operation, the Control Module will add fuel (enriches the mixture) when the HO2S detects a lean exhaust content and subtract fuel (leans-out the mixture) when the HO2S detects a rich exhaust condition.
Certain vehicle models utilize an oxygen sensor after the catalyst converter in order to monitor catalyst efficiency.
This DTC determines if the HO2S is functioning properly by checking for an adequate number of HO2S voltage transitions above and below the bias range of 300-600 mV. This DTC sets when the VCM fails to detect a minimum number of voltage transitions above and below the bias range during the test period. Possible causes of this DTC are listed below.
Important: This test is void if the system voltage remains outside the specified range for more than 4 seconds
The HO2S sensor voltage remains within 150 mV of the start-up voltage for 130 seconds after cold start.
Action Taken When the DTC Sets
Important: Never solder the HO2S wires.
Check for the following conditions:
An intermittent may be caused by any of the following conditions:
Test Description
The number(s) below refer to the step number(s) on the Diagnostic Table.
2. As the heater warms the oxygen sensor to operating temperature, the HO2S will output a voltage in relation to the amount of oxygen in the exhaust. With the ignition ON and the engine OFF the exhaust usually contains a high oxygen content. With the engine OFF the HO2S voltage will usually decrease from the initial (bias) voltage due to the high oxygen content.
4. This step checks for proper HO2S heater ignition feed and ground supply.
5. This step checks for proper VCM and signal circuit operation.
---------- Post added at 10:38 PM ---------- Previous post was at 10:32 PM ----------
something else caused these codes. while it records the misfire code and o2 codes it is a sign the fuel mixture got way out of line. the p0300 is informative only and the p0151 is more of a annunciation of a monitor malfunction but not really caused by it self. in other words those codes did not stop you. something mixture burned vs unburned shut you down. fuel pressure or ignition fault or a highly unlikely catastrophic loss of compression. no indication tho that a sensor is the cause tho yet.
---------- Post added at 10:38 PM ---------- Previous post was at 10:38 PM ----------
a misfire history will help to narrow causes.
Circuit Description
The Heated Oxygen Sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The Control Module (PCM/VCM) supplies the HO2S with signal High and Low circuits. Ignition voltage and ground is supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs leaner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.
The HO2S contains a heater that is necessary in order to quickly warm the sensor to operating temperature and maintain the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. Once the HO2S has reached operating temperature, the Control Module monitors the HO2S bias, or reference, voltage as well as the HO2S signal voltage for closed loop fuel control. During normal Closed Loop fuel control operation, the Control Module will add fuel (enriches the mixture) when the HO2S detects a lean exhaust content and subtract fuel (leans-out the mixture) when the HO2S detects a rich exhaust condition.
Certain vehicle models utilize an oxygen sensor after the catalyst converter in order to monitor catalyst efficiency.
This DTC determines if the HO2S is functioning properly by checking for an adequate number of HO2S voltage transitions above and below the bias range of 300-600 mV. This DTC sets when the VCM fails to detect a minimum number of voltage transitions above and below the bias range during the test period. Possible causes of this DTC are listed below.
- An open or a short to voltage on either the HO2S signal or HO2S low circuits.
- A malfunctioning HO2S.
- A problem in the HO2S heater or its circuit.
- A poor HO2S ground.
- An open circuit in either the HO2S ignition positive voltage or the HO2S heater ground circuits.
- An HO2S heater element problem.
Important: This test is void if the system voltage remains outside the specified range for more than 4 seconds
- The system voltage is between 11.7-18 volts
- The MAF is less than 27 g/s 5.0L (35 g/s 5.7L)
- The engine run time is more than 2 seconds
- The ECT is less than 33°C (91°F)
- The IAT is less than 33°C (91°F)
- The difference between the ECT and IAT is 5°C (9°F) or less
The HO2S sensor voltage remains within 150 mV of the start-up voltage for 130 seconds after cold start.
Action Taken When the DTC Sets
- The Control Module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
- The Control Module will set the DTC and records the operating conditions at the time the diagnostic fails. The Control Module stores the failure information in the scan tools Freeze Frame and/or the Failure Records.
- The Control Module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the Engine Coolant Temperature is more than 70°C (158°F) during the same ignition cycle).
- Use the scan tool Clear Information function.
Important: Never solder the HO2S wires.
Check for the following conditions:
An intermittent may be caused by any of the following conditions:
- A poor connection
- Rubbed through wire insulation
- A broken wire inside the insulation
Test Description
The number(s) below refer to the step number(s) on the Diagnostic Table.
2. As the heater warms the oxygen sensor to operating temperature, the HO2S will output a voltage in relation to the amount of oxygen in the exhaust. With the ignition ON and the engine OFF the exhaust usually contains a high oxygen content. With the engine OFF the HO2S voltage will usually decrease from the initial (bias) voltage due to the high oxygen content.
4. This step checks for proper HO2S heater ignition feed and ground supply.
5. This step checks for proper VCM and signal circuit operation.
---------- Post added at 10:38 PM ---------- Previous post was at 10:32 PM ----------
something else caused these codes. while it records the misfire code and o2 codes it is a sign the fuel mixture got way out of line. the p0300 is informative only and the p0151 is more of a annunciation of a monitor malfunction but not really caused by it self. in other words those codes did not stop you. something mixture burned vs unburned shut you down. fuel pressure or ignition fault or a highly unlikely catastrophic loss of compression. no indication tho that a sensor is the cause tho yet.
---------- Post added at 10:38 PM ---------- Previous post was at 10:38 PM ----------
a misfire history will help to narrow causes.
Yukon420SEL
Member
yup +1 on the cps
slipping
Full Access Member
Thanks guys, I'll do some trouble shooting
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