No voltage to o2 sensor 1

some codes dont cause power loss or may not even notice anything wrong but a check engine light a p0152 code means following answer courtesy of OBD-CODES.com === P0152 O2 Sensor (High Voltage) OBD-II Trouble Code Technical Description Article by Dale Dale Toalston ASE Certified Technician 02 Sensor Circuit High Voltage (Bank 2 Sensor 1) What does that mean? The o2 (oxygen) sensors basically measure oxygen content in the exhaust. The PCM (powertrain control module) then uses this information to regulate fuel injector pulse. The o2 sensors are very important to proper operation of the engine. Problems with them can cause the PCM to add or take away too much fuel based on the faulty o2 sensor voltage. A P0152 code refers to the Bank 2, sensor 1, o2 sensor. (Bank 1 would contain cylinder 1 and bank 2 is the opposite bank. Bank 2 doesn't necessarily contain cylinder 2.) "Bank 2" refers to the side of the exhaust that DOES NOT contain cylinder number 1 and "Sensor 1" indicates that it is the pre-cat sensor, or forward(first) sensor on that bank. It is a four wire sensor. The PCM supplies a ground circuit and a reference voltage of about .5 volts on another circuit. Also for the o2 heater there is a battery voltage supply wire and another ground circuit for that. The o2 sensor heater allows the o2 sensor to warm up faster, thus achieving closed loop in less time than it would normally take for the exhaust to warm the sensor up to operating temperature. The O2 sensor varies the supplied reference voltage based on oxygen content in the exhaust. It is capable of varying from .1 to .9 volts, .1 indicating lean exhaust and .9 indicating rich exhaust. NOTE: A condensed explanation of fuel trims: If the o2 sensor indicates that the oxygen voltage reading is .9 volts or high, the PCM interprets this as a rich condition in the exhaust and as a result decreases the amount of fuel entering the engine by shortening injector "on time". The STFT (short term fuel trims) would reflect this change. The opposite would occur when the PCM sees a lean condition. The PCM would add fuel which would be indicated by a single digit positive STFT reading. On a normal engine the front o2 sensors switch rapidly back and forth two or three times per second and the STFT would shift positive and negative single digits to add and remove fuel to compensate at a similar rate. This little "dance" goes on to keep the air/fuel ratio at it's optimal level. Short term fuel trims or STFT reflect immediate changes in fuel injector "on-time" while long term fuel trims or LTFT reflect changes in fuel over a longer period of time. If your STFT or LTFT readings are in the positive double digits (ten or above), this indicates the fuel system has been adding an abnormal amount of fuel than is necessary to keep the proper air/fuel ratio. It may be overcompentsating for a vacuum leak or a stuck lean o2 sensor, etc. The opposite would be true if the fuel trim readings are in the negative double digits. It would indicate that the fuel system has been taking away excessive amounts of fuel, perhaps to compensate for leaking injectors or a stuck rich o2 sensor, etc. So when experiencing o2 related issues, reading your fuel trims can indicate what the PCM has been doing over the long term and short term with regard to fuel. This code indicates that the o2 sensor was stuck too high or in the rich position. The PCM monitors this voltage and if it determines that the voltage is too high out of range for too long, P0152 may set. Symptoms Symptoms may include: MIL (Malfunction Indicator Lamp) illumination Engine may run very rough Engine may be running lean or rich depending on if the o2 sensor is reading correctly or incorrectly Lack of power Increased fuel consumption Causes Potential causes of an P0152 code include: Bad bank 2, 1 o2 sensor incorrectly reading rich condition Engine running rich and o2 sensor Correctly reading rich condition Signal shorted to voltage in harness Wiring harness damage/melted due to contact with exhaust components Vacuum leak (make have lean codes (P0171, P0174) present with it) Leaking injectors Bad fuel pressure regulator Bad PCM Possible Solutions If you have any lean or rich codes associated with this code, focus on fixing these first because these can cause the o2 sensor voltage readings to appear to be faulty when they are in fact only reading correctly. So, with the engine running at operating temperature, use a scan tool to observe the Bank 2,1 o2 sensor voltage reading. Is it high? If so, look at the long term and short term fuel trim readings. The fuel trims are affected by the o2 sensors as noted above. If the LTFT reading for that bank is indicating negative double digits (PCM trying to take away fuel to compensate for problem) try inducing a vacuum leak to see if the sensor voltage then goes lean and the fuel trims increase. If the o2 sensor responds, suspect a problem with the engine, not the sensor. There may be other engine codes to help you. If the o2 sensor reading remains high (0.9 volts or above) and won't respond then shut off engine. With KOEO (Key on engine off) disconnect the o2 sensor and look for signs of corrosion or water intrustion. Repair as necessary. The voltage reading should now be about 0.5 volts. If so, replace the o2 sensor, it's shorted internally. If after unplugging the o2 sensor the voltage reading on the scan tool doesn't change, then suspect wiring problems. Inspect the harness and look for any melted wires or anywhere that the o2 sensor harness is making contact with the exhaust components. If you are unsure, you can check for continuity of all four wires between the sensor and the PCM with an ohmmeter. Any resistance at all indicates a problem. Repair as necessary.

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This code is for a post-catalyst oxygen sensor that isn't operating properly or not at all. The catalyst, or catalytic converter is used to control emissions. This particular o2 sensor on Bank 2, position 2 is after the converter on bank 2 and monitors the catalyst efficiency of the catalytic converter on that bank. The P.C.M (Power train Control Module) compares the post-cat o2 sensor to the pre-cat o2 sensors to measure the cat's efficiency. The o2 sensor is a four wire sensor. The P.C.M supplies a reference voltage to the sensor of about half a volt and also supplies a sensor ground. 12 volts are supplied for the heater element and also a ground for the heater element (the heater in the sensor helps the sensor to warm up faster which allows the engine to reach closed loop sooner). The sensor varies the reference voltage the P.C.M gives it based on oxygen content of the exhaust. The change in oxygen content causes resistance changes in the sensor which affects the 0.5 volt reference voltage. Oxygen sensors are capable of varying the supplied voltage between 0.1 volts to 0.9 volts. Lean exhaust produces low voltage and causes the supplied 0.5 volts to drop. Rich exhaust produces high voltage and causes the supplied 0.5 voltage to increase. Pre-catalyst (front) o2 sensors switch between low and high voltage rapidly one or two times per second. However this sensor is a post-cat o2 sensor and may switch much slower & not vary as much (this is normal). If the sensor "sticks" or there are too few switches in a given time period, P0160 may set.

Intermittent condition Restricted fuel supply line Fuel pump inlet strainer plugged Fuel pump module O2 sensor heater operation O2 sensor EVAP system operation O2 sensor signal circuit shorted to voltage O2 sensor signal circuit open TPS voltage greater than 0.92 volts with throttle closed Throttle position sensor sweep MAP sensor operation ECT sensor operation Engine mechanical problem Fuel filter/pressure regulator (high)

this obd2 trouble code table can help you understand the meaning of code. And for your code, you can try following:
Using a scan tool, determine if the Bank 1, sensor 1 is switching properly. It should switch rapidly between rich and lean, evenly

1. If it does, the problem is likely intermittent and you should examine the wiring for any visible damage. Then perform a wiggle test by manipulating the connector and wiring while watching the o2 sensor voltage. If it drops out, fix the appropriate part of the wiring harness where problem resides.

2. If it doesn\'t switch properly, try to determine if the sensor is accurately reading the exhaust or not. Do this by removing the fuel pressure regulator vacuum supply briefly. The o2 sensor reading should go rich, reacting to the extra fuel added. Reinstall regulator supply. Then induce a lean condition by removing a vacuum supply line from the intake manifold. The o2 sensor reading should go lean, reacting to the enleaned exhaust. If the sensor operates properly, then the sensor may be okay and the problem may be holes in the exhaust or an unmetered vacuum leak in the engine (NOTE: Unmetered vacuum leaks at the engine are almost always accompanied by lean codes. Refer to the appropriate articles for diagnosing an unmetered vacuum leak). If the exhaust does have holes in it, it's possible that the o2 sensor may be misreading the exhaust because of the extra oxygen entering the pipe via those holes

3. If none of this is the case and the o2 sensor just isn't switching or acts sluggish, unplug the sensor and make sure there is 5 Volt reference voltage to the sensor. Then check for 12V supply to the o2 sensor's heater circuit. Also check for continuity to ground on the ground circuit. If any of these are missing, or aren't their proper voltage, repair open or short in the appropriate wire. The o2 sensor will not operate properly without proper voltage. If the proper voltages are present, replace the o2 sensor.

Using a scan tool, determine if the Bank1, sensor 1 is switching properly. It should switch rapidly between rich and lean, evenly.

1. If it does, the problem is likely intermittent and you should examine the wiring for any visible damage. Then perform a wiggle test by manipulating the connector and wiring while watching the o2 sensor voltage. If it drops out, fix the appropriate part of the wiring harness where problem resides.

2. If it doesn\'t switch properly, try to determine if the sensor is accurately reading the exhaust or not. Do this by removing the fuel pressure regulator vacuum supply briefly. The o2 sensor reading should go rich, reacting to the extra fuel added. Reinstall regulator supply. Then induce a lean condition by removing a vacuum supply line from the intake manifold. The o2 sensor reading should go lean, reacting to the enleaned exhaust. If the sensor operates properly, then the sensor may be okay and the problem may be holes in the exhaust or an unmetered vacuum leak in the engine (NOTE: Unmetered vacuum leaks at the engine are almost always accompanied by lean codes. Refer to the appropriate articles for diagnosing an unmetered vacuum leak). If the exhaust does have holes in it, it's possible that the o2 sensor may be misreading the exhaust because of the extra oxygen entering the pipe via those holes

3. If none of this is the case and the o2 sensor just isn't switching or acts sluggish, unplug the sensor and make sure there is 5 Volt reference voltage to the sensor. Then check for 12V supply to the o2 sensor's heater circuit. Also check for continuity to ground on the ground circuit. If any of these are missing, or aren't their proper voltage, repair open or short in the appropriate wire. The o2 sensor will not operate properly without proper voltage. If the proper voltages are present, replace the o2 sensor.

Causes

Potential causes of an P0156 code include:

• Bad O2 sensor
• Signal shorted to voltage
• Wiring problems due to contact with exhaust components
• Holes in exhaust near o2 sensor

Possible Solutions

If you have access to a scan tool, check the signal voltage for the Bank 2,2 oxygen sensor with the engine at normal operating temperature. Is it stuck low currently? If so, increase RPM for a few seconds and see if it affects the reading. If it begins working with increased RPM, check for holes in the exhaust near the o2 sensor that may cause a false lean. If the exhaust pipe is intact, the sensor is sluggish, replace it.

If the Bank 2,2 o2 sensor voltage reading remains low with increased RPM, unplug it and then observe the reading. It should have increased to about 0.5 volts or thereabouts. If it did, check for water intrusion or other connector problems. If none are found, replace the shorted o2 sensor. If the voltage reading is still stuck low after unplugging the sensor, then suspect a wiring problem. Using a voltmeter, with the o2 sensor unplugged, check for voltage on the signal circuit at the o2 sensor connector(PCM side). It can vary with model, but should be about 0.5 volts and not above 1 volt. If the voltage reading is too high, repair short to voltage on signal circuit. If the signal voltage checks out, suspect the PCM.

P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
This code refers to the front oxygen sensor on Bank 2. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0155. See also: P0135 (Bank 1).

Potential Symptoms: You will likely notice poor fuel economy the illumination of the MIL.

Causes: A code P0155 may mean that one or more of the following has happened:
O2 Heater element resistance is high
Internal short or open in the heater element
O2 heater circuit wiring high resistance
open or short to ground in the wiring harness

Possible Solutions:
Repair short or open or high resistance in wiring harness or harness connectors
Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)



P0156 - 02 Sensor Circuit Malfunction (Bank 2 Sensor 2)
The o2 (oxygen) sensors measure oxygen content in the exhaust. The PCM (powertrain control module) then uses this information to regulate fuel injector pulse. The o2 sensors are very important for the proper operation of the engine. Innacurate or faulty o2 sensors can cause the PCM to add or take away fuel based on the faulty o2 sensor voltage which can cause a host of problems.

A P0156 code refers to the Bank 2,2 o2 sensor or the downstream (post-cat) o2 sensor on Bank 2. It is a four wire sensor. The PCM supplies a ground circuit and a reference voltage circuit of about 0.5 volts. Also for the o2 sensor heater element there is a battery voltage supply wire and another ground circuit for that. The o2 sensor heater allows the o2 sensor to warm up faster, thus achieving closed loop in less time than it would normally take for the exhaust to warm the sensor up to operating temperature. The O2 sensor varies the supplied reference voltage based on oxygen content in the exhaust. It is capable of varying from about 0.1 to 0.9 volts, 0.1 V indicating lean exhaust and 0.9 V indicating rich exhaust. This P0156 code indicates that the Bank 2, 2 o2 sensor is stuck low for too long or isn\'t active at all.

Symptoms: Often post-cat o2 sensor problems present few symptoms since they are inputs to the PCM to monitor catalytic converter quality and don\'t directly control fuel. sometimes no symptoms are noticeable. However the following may be possible on some vehicles:
MIL (Malfunction Indicator Lamp) illumination
Decrease in MPG
Increase in tailpipe emissions

Causes: Potential causes of an P0156 code include:
Bad O2 sensor
Signal shorted to voltage
Wiring problems due to contact with exhaust components
Holes in exhaust near o2 sensor

Possible Solutions:
If you have access to a scan tool, check the signal voltage for the Bank 2,2 oxygen sensor with the engine at normal operating temperature. Is it stuck low currently? If so, increase RPM for a few seconds and see if it affects the reading. If it begins working with increased RPM, check for holes in the exhaust near the o2 sensor that may cause a false lean. If the exhaust pipe is intact, the sensor is sluggish, replace it.

If the Bank 2,2 o2 sensor voltage reading remains low with increased RPM, unplug it and then observe the reading. It should have increased to about 0.5 volts or thereabouts. If it did, check for water intrusion or other connector problems. If none are found, replace the shorted o2 sensor. If the voltage reading is still stuck low after unplugging the sensor, then suspect a wiring problem. Using a voltmeter, with the o2 sensor unplugged, check for voltage on the signal circuit at the o2 sensor connector(PCM side). It can vary with model, but should be about 0.5 volts and not above 1 volt. If the voltage reading is too high, repair short to voltage on signal circuit. If the signal voltage checks out, suspect the PCM.


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Grand Cherokee oxygen sensor locations for 4.0 and 4.7 engines...






An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the amount of oxygen in the exhaust. In other words, if the oxygen content is low, the voltage output is high; if the oxygen content is high the output voltage is low. The PCM uses this information to adjust injector pulse-width to achieve the 14.7-to-1 air/fuel ratio necessary for proper engine operation and to control emissions.

The O2 sensor must have a source of oxygen from outside of the exhaust stream for comparison. Current O2 sensors receive their fresh oxygen (outside air) supply through the O2 sensor case housing.

Four wires (circuits) are used on each O2 sensor:
* 12-volt feed circuit for the sensor heating element
* Ground circuit for the heater element
* Low-noise sensor return circuit to the PCM
* Input circuit from the sensor back to the PCM to detect sensor operation


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P0147 - 02 Sensor Heater Circuit Malfunction (Bank I Sensor 3)

O2 (Oxygen) sensors contain a heating element that allows the sensor to reach operating temperature quickly. This lowers emissions since it allows the engine to reach closed loop faster and also allows the engine to stay in closed loop at idle. The heater circuit is supplied a 12 V battery feed from the PCM or ignition circuit (depending on model) and a ground. The PCM (powertrain control module) monitors how long it takes for the sensors to become active after engine start-up. If it takes too long for the o2 sensors to reach operating temperature, this P0147 can set.

Symptoms: For this particular o2 sensor, there may be no noticeable symptoms other than:
* MIL (Malfunction Indicator Lamp) illumination
* Poor/ rough idle

Causes: Potential causes of an P0147 code include:
* Bad o2 sensor heater circuit
* Bad o2 sensor
* Wiring harness problems

Possible Solutions: Unplug the Bank 1, 3 sensor. With KOEO (key on engine off) use a voltmeter to check for battery voltage present at the o2 sensor connector (PCM side). (You can also do this with a test light. Connect to ground and touch lead to heater circuit supply. Light should illuminate with KOEO) You should have battery voltage present.

a. If voltage is present, check the ground side of the heater element also making sure a good ground is present. If it is, check for any faulty connections & then replace the o2 sensor. If you don't have a good ground, then there is an open in the ground circuit somewhere that will need to be repaired. Look for wiring harness contact with exhaust components or broken/missing connectors, etc.

b. If battery voltage isn't present with KOEO, check for a blown fuse supplying the heater elements. You may need to get a wiring diagram for this. If the fuse is blown, you'll need to check for a short to ground on the battery supply circuit before replacing the fuse. If you find none, and replacing the fuse re-establishes battery voltage at the o2 sensor connector, then the o2 sensor may have shorted internally, blowing the fuse. Replace it & recheck. (NOTE: it's possible for an o2 sensor's heater circuit to be open/shorted and the o2 sensor to still function).

c. If you have no battery voltage present with KOEO and there are no blown fuses supplying the heater circuit, then check for an open on the supply circuit. You can do this by ohming the circuit with the o2 sensor unplugged and the PCM unplugged. Repair and recheck.


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That is the oxygen sensor on bank 1 down by the cat converter.