2 problems with 1999 jeep cherokee sport 4x4

Hi Amanda , I want to help you with your question, but I need more information from you. Can you please add details in the comment box?
USA car or NOT? USA is WJ jeep gas engines.
sensor B2S1 is bad. or worse.
or wires to it burned up , clamps bad and wires hit red hot
exhaust pipe
no engine told 4.0L i6 or 4.7L v8
must be v8. bank 2.

the front sensor is bad (aka upstream)
bank 2 is not cylinder 1 bank.
on USA car , bank2, seated in driver side
is right bank of engine is 2.
facing said engine is left bank.2.
the sensor is here

in the USA there are 2 v8 smog parts, CALF or FED

seen here clearly in the service manual oem I have in hand



the 4.0 liter is very trick this year,
it has an odd splite exh manifold
but only seen on calif engines,
see next photo for 4.0L engine,

Question edited to fix second code.
Grand Cherokee P0700 Code Definition If you are scanning your vehicle right now, you should be looking for a second code that tells you what is actually wrong. Think about it like this.

• P0700 Says- "Hey there's something wrong with this transmission.
• The Next Code(s) Say- "I'm the actual problem going on with the transmission. I'm what you're looking for."

Ways to fix
https://www.google.com/search?q=jeep+grand+cherokee+p0700+problem

And P0038

Jeep P0038 HO2S Heater Control Circuit High Bank 1 Sensor 2

https://www.carobdcodes.com > jeep-p0038-ho2s-heate...
OBD-II Trouble Code Description for P0038 Jeep ... Jeep Grand Cherokee SRT8,2006 Jeep Commander 4×4 Limited 5.7 HEMI,2005 Jeep Wrangler UK Version,2005 Jeep ...

P0038 JEEP Code - O2 Sensor 1/2 Heater Circuit High

https://www.autocodes.com > p0038_jeep
Jul 13, 2020 - Repair Information for P0038 Jeep code. Learn what O2 Sensor 1/2 Heater Circuit High means, location and how to repair?

..

• Dale, code P0171 fuel system too lean
• Possible causes
• change fuel filter first, if it has not been done recently

RESTRICTED FUEL SUPPLY LINE
FUEL PUMP INLET STRAINER PLUGGED
FUEL PUMP MODULE
O2 SENSOR
O2 SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
O2 SENSOR HEATER OPERATION
TPS VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
TP SENSOR SWEEP
MAP SENSOR OPERATION
ECT SENSOR OPERATION
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR (HIGH)
PCM
Check the attached links,
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2000 Jeep Grand Cherokee p0171

Possible problems related to Code P0171 Jeep Garage Jeep Forum

P0171 System to Lean Bank 1

Code P0171

P0138 - O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)

The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)

Symptoms: There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.

Causes: A code P0138 may mean that one or more of the following has happened:
* Faulty O2 sensor
* Short to battery voltage in O2 sensor signal circuit
* High fuel pressure (not as likely)

Possible Solutions: Here are some potential solutions:
* Replace O2 sensor
* Repair short to battery voltage in o2 sensor signal circuit

Hope helps (remember to rate and comment this).

Your O2 sensor needs to be replaced. These sensors constantly out put voltage from .1 volts up to 1.3 volts, your sensor is stuck in the high range. It is the first O2 closest to the engine.

P0137 - Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)

Essentially the same as P0136, P0137 refers to the second oxygen sensor on Bank 1. P0137 means the O2 oxygen sensor's voltage remained low for longer than 2 minutes. This, is interpreted by the ECM as a low voltage condition and sets the MIL. Bank 1 Sensor 2 is located to the rear of the catalytic converter and should produce an output signal relative to oxygen storage capacity of the catalytic converter. This rear (sensor 2) sensor is less active than the signal produced by the front sensor. However, if the ECM senses the sensor is inactive, this code will set.

Symptoms: There may be no visible symptoms to the driver, other than the MIL (Check Engine / Service Engine Soon) illumination.

Causes: A code P0137 may mean that one or more of the following has happened:
* Faulty o2 sensor Exhaust leak near the rear sensor
* Plugged catalyst
* Short to voltage on O2 signal circuit
* High resistance or open on O2 signal circuit

Possible Solutions:
* Replace faulty sensor
* Repair exhaust leak near the rear sensor
* Check for restriction in catalyst and replace as necessary
* Repair short, open, or high resistance on o2 signal circuit

Hpe hti shelps (remember comment and rated this).

Grand Cherokee oxygen sensor locations for 4.0 and 4.7 engines







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

O2S Sensor removal Never apply any type of grease to the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.
WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER(S) BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.
1. Raise and support vehicle.
2. Disconnect O2S pigtail harness from main wiring harness.
3. If equipped, disconnect sensor wire harness mounting clips from engine or body.
CAUTION: When disconnecting sensor electrical connector, do not pull directly on wire going into sensor.
4. Remove O2S sensor with an oxygen sensor removal and installation tool.

02S Sensor installation
Threads of new oxygen sensors are factory coated with anti-seize compound to aid in removal. DO NOT add any additional anti-seize compound to threads of a new oxygen sensor.
1. Install O2S sensor. Tighten to 22 ft. lbs. (30 N·m) torque.
2. Connect O2S sensor wire connector to main wiring harness.
3. If equipped, connect sensor wire harness mounting clips to engine or body. When Equipped: The O2S pigtail harness must be clipped and/or bolted back to their original positions on engine or body to prevent mechanical damage to wiring.


Hope thats help (remember comment and rated this).

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

my jeep is flashing code 12 and 21

Sensor #1 is the sensor before the converter (upstream sensor)