I'm getting 3 codes on my ECU 21-33-51 . I have replaced my ECU , replaced all injectors and oxygen heat sensor. The new ECU is showing the same codes.

• P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
• P0171 System Too Lean (Bank 1)

Hi Michael, After fixing errors you need to reset your computer by disconnecting the battery for a minute or two, Also you'll need your radio code to reset your radio, I hope this helped...........CHEERS..

159, (USA?) must be V6 or V8 it has 2 banks.
first google hit
Possible causes
- Faulty Rear Heated Oxygen Sensor Bank 2
- Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks may be faulty
- Exhaust gas leaks

let me condense this.
1: the right bank rear 02 sensors is reading wrong,
note I did not say it was bad. dig?
2: this means the CAT on that side, is UNHAPPY.

unhappy can be , as it said air leaks anywhere near the front or rear of Bank 2 CAT.
unhappy 2, is the engine fuel controls are totally out of control
way rich or lean, out of control;
unhappy3, gross misfire, or all the above at once.

the ECU(pcm) at no time ever KNOW what is wrong, it only can flag bad inputs. or tests that fail , tests are called (USA,OBD2 SAE) called Monitors.
do you have a full can tool? or just a near useless codereader.
?

P0050 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 1)

P0051 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 1)

P0052 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 1)

P0053 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 1)

P0054 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 2)

P0055 HO2S Heated Oxygen Sensor -Resistance (Bank 1 Sensor 3)

P0056 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 2)

P0057 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 2)

P0058 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 2)

P0059 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 1)

P0060 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 2)

P0061 HO2S Heated Oxygen Sensor -Resistance (Bank 2 Sensor 3)

P0062 HO2S Heated Oxygen Sensor -Control Circuit (Bank 2 Sensor 3)

P0063 HO2S Heated Oxygen Sensor -Control Circuit Low (Bank 2 Sensor 3)

P0064 HO2S Heated Oxygen Sensor -Control Circuit High (Bank 2 Sensor 3)

P0065 Air Assisted Injector -Range/Performance

P0066 Air Assisted Injector -Circuit Malfunction or Circuit Low

P0067 Air Assisted Injector -Circuit High

P0068 (MAP) Manifold Absolute Pressure /(MAF) Mass Air Flow - Throttle Position

Correlation

P0069 (MAP) Manifold Absolute Pressure / (BARO)Barometric Pressure Correlation

P0070 Ambient/Outside Air Temperature Sensor -Circuit Malfunction

P0071 Ambient/Outside Air Temperature Sensor -Range/Performance Problem

P0072 Ambient/Outside Air Temperature Sensor -Circuit Low Input

P0073 Ambient/Outside Air Temperature Sensor -Circuit High Input

P0074 Ambient/Outside Air Temperature Sensor -Circuit Intermittent

P0075 Intake Valve Control Solenoid Circuit Malfunction (Bank 1)

P0076 Intake Valve Control Solenoid Circuit Low (Bank 1)

P0077 Intake Valve Control Solenoid Circuit High (Bank 1)

P0078 Exhaust Valve Control Solenoid Circuit Malfunction (Bank 1)

P0079 Exhaust Valve Control Solenoid Circuit Low (Bank 1)

P0080 Exhaust Valve Control Solenoid Circuit High (Bank 1)

P0081 Intake valve Control Solenoid Circuit Malfunction (Bank 2)

P0082 Intake Valve Control Solenoid Circuit Low (Bank 2)

P0083 Intake Valve Control Solenoid Circuit High (Bank 2)
P0084 Exhaust Valve Control Solenoid Circuit Malfunction (Bank 2)

P0170 Fuel Trim (Bank 1)
____________
new version fgtech v53

p0132 is heated oxygen sensor.......wiring short to positive
and p1132 is heated oxygen sensor not switching, fuel trim, rich mixture.......intake/fuel system injectors MAF sensor, ECT sensor. hope this helps and if you need any more info just ask

I think your reverse to park trick was a fluke,, I assume it turns over but since it is a 1995 you dont have a OBD 2 in the vehicle.
How to pull ECU error codes for 87-95 Pathfinders and Hardbody pickups:


The ECU is under your passenger's side seat. You can gain access to it by simply sliding the seat all the way forward and removing the plastic cover from the ECU. You can also remove the seat if you want, it makes access a little easier.

The VG30i ECU's have a tiny toggle switch on the side of the ECU with a small snap-in switch cover that must be utilized to select the diagnostic mode of the ECU. The 4-cylinder ECU and the VG30E ECU has a slotted switch that turns 1/4 or 1/2 turn clockwise and counterclockwise to do the same task. Some early 4-cyl HB ECU's have the switch as well. In any case it will have one or the other.

For 4-cylinder:
1. Turn the ignition switch on, but do not start the engine. All of the lights in the dash should be on.
2. Turn the 'diagnostic mode selector' screw on the ECU fully clockwise. The check engine light will go out. Wait 5 seconds, then turn the screw fully counter clockwise.
3. The check engine light will then begin to flash the trouble code. (number of long flashes is the 1st digit, number of short flashes is the 2nd digit)
4. To clear all stored codes and turn the check engine light off, turn the screw fully clockwise while it is in diagnostic mode. Wait 5 seconds, then turn the screw fully counter clockwise.
5. To keep the codes stored, simply turn the key off as the check engine
light is flashing and the ECU will keep all stored codes and the check engine light will remain on.

For V6:
1. Turn the ignition switch on, but do not start the engine. All of the lights in the dash should be on.
2. For VG30i: There is a little plastic tab you pull off of the side of the ECU(facing the door). A small toggle switch is behind it with 2 positions, "ON" and "DIAGNOSTICS". Using a small screwdriver or tool, move it to the diagnostics position. The red and green LED's on top of the ECU will blink simultaneously. One time, pause, then 2 times, three times, pause...so on for each mode, 1 through 5. Mode 3 is the most commonly used mode and will yield the ECU trouble codes you need to figure out what's going on with your engine.
For VG30E with slotted switch: Turn the 'diagnostic mode selector' screw on the ECU fully clockwise. The check engine light will go out. Wait 5 seconds, then turn the screw fully counter clockwise.
3. After it blinks both LED's 3 times move the toggle switch back to the on position. After about five seconds it will start to output out the diagnostic codes as with the 4-cylinder ECU. Note each code as it is displayed, the red LED flashing once for 10's, and the green LED flashing once for 1's. Meaning: One red flash and two green flashes means code 12.
4. To clear the ECU of any trouble codes, move the switch to the "DIAGNOSTICS" position then back to the "ON" position and turn off the key.

1986.5-1995 Nissan ECU Flash Codes(all engines)

11 Crank Angle Sensor/Camshaft Position Sensor.
12 Air Flow Meter/Mass Air Flow Sensor.
13 Engine Coolant Temperature Sensor.
14 Vehicle Speed Sensor.
21 Ignition Signal.
22 Fuel Pump.
23 Idle Switch.
24 Throttle Valve Switch.
25 Idle Speed Control Valve.
28 Cooling Fan Circuit.
31 ECM.
32 EGR Function.
33 Heated Oxygen Sensor.
34 Knock Sensor.
35 Exhaust Gas Temperature Sensor.
36 EGR Control-Back Pressure Transducer.
37 Knock Sensor.
38 Right hand bank Closed Loop (B2).
41 Intake Air Temperature Sensor.
42 Fuel Temperature Sensor.
43 Throttle Position Sensor.
44 ECCS Normal Operation.
45 Injector Leak.
47 Crankshaft Position Sensor.
51 Injector Circuit.
53 Oxygen Sensor.
54 A/T Control.
55 No Malfunction.
63 No. 6 Cylinder Misfire.
64 No. 5 Cylinder Misfire.
65 No. 4 Cylinder Misfire.
66 No. 3 Cylinder Misfire.
67 No. 2 Cylinder Misfire.
68 No. 1 Cylinder Misfire.
71 Random Misfire.
72 TWC Function right hand bank.
73 TWC Function right hand bank.
76 Fuel Injection System Function right hand bank.
77 Rear Heated Oxygen Sensor Circuit.
82 Crankshaft Position Sensor.
84 A/T Diagnosis Communication Line.
85 VTC Solenoid Valve Circuit.
86 Fuel Injection System Function right hand bank.
87 Canister Control Solenoid Valve Circuit.
91 Front Heated Oxygen Sensor Heater Circuit right hand bank.
94 TCC Solenoid Valve.
95 Crankshaft Position Sensor.
98 Engine Coolant Temperature Sensor.
101 Front Heated Oxygen Sensor Heater Circuit right hand bank.
103 Park/Neutral Position Switch Circuit.
105 EGR and EGR Canister Control Solenoid Valve Circuit.
108 Canister Purge Control Valve Circuit

ECU Diagnostic Mode Procedures
Mode I - Exhaust Oxygen Sensor Monitor
-----------------------------------------------------------------------
Use Mode I to determine if the Oxygen Sensor is functioning properly.

Warm the engine to normal temperature.
Run the engine above 2000 RPM under no load while looking at the ECU.
Make sure the GREEN LED goes on and off more than five times during ten seconds at 2000 RPM.
If the number of flashes are not more than five, replace the oxygen sensor. If the LED does not flash, check the sensor's circuit.


Mode II - Mixture Ratio Control Monitor
-----------------------------------------------------------------------
Use Mode II to determine if the air/fuel mixture is cycling correctly.

Warm the engine to normal operating temperature.
Turn the dial on the ECU fully clockwise (or if you have a switch, turn it on).
After the LED flashes twice, turn the dial fully counter clockwise (or turn the switch off).
Run the engine above 2000 RPM under no load while looking at the ECU.
If the RED LED blinks simultaneously with the GREEN LED, the air/fuel mixture is cycling properly.
If the RED LED stays off, the mixture is more than 5% rich.
If the RED LED stays on, the mixture is more than 5% lean.
If the RED LED stays on or off above 2000 RPM, complete the diagnostics before beginning repairs.


Mode III - Stored Fault Code Reporting
-----------------------------------------------------------------------
Use Mode III to retrieve all stored trouble codes in memory.
Use the above posted procedures.


Mode IV - Switch Operation Monitor
-----------------------------------------------------------------------
Use Mode IV to determine if the Throttle Position Sensor (TPS), Starter circuit and/or Vehicle Speed Sensor (VSS) are in proper working order.

Turn the ignition switch on, but do not start the engine.
Turn the dial on the ECU fully clockwise. After the LED flashes 4 times, turn the dial fully counter clockwise.
Make sure the RED LED is turned off.
Make sure the RED LED turns on when depressing the gas pedal. If not, check or replace the Throttle Position Sensor.
Make sure the RED LED turns on when turning the ignition key the START position. If not, check or replace the starter.
Drive the vehicle with the ECU unbolted and within view. Make sure the GREEN LED turns on when speed is 12 MPH or more. If not, check or replace the Vehicle Speed Sensor.


Mode V - Real Time Diagnostic Function
-----------------------------------------------------------------------

Use Mode V to determine if the Crankshaft Position Sensor (CPS), Mass Air Flow Sensor (MAFS) and/or Ignition signal are working properly.

Start engine.
Turn the dial on the ECU fully clockwise.
After the LED flashes 5 times, turn the dial fully counter clockwise.
Make sure LEDs do not flash for 5 minutes when racing or idling the engine.
If it flashes, count the number of flashes, turn engine off, and see the following 3 paragraphs. Perform real-time diagnosis inspection and repair or replace malfunctioning part if present.
if LEDs do not flash for 5 minutes, turn engine off.

If the RED LED flashes 3 times for 1.5 seconds, check the Crankshaft Position Sensor. Check the harness continuity at CPS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.

If the GREEN LED flashes twice-3 times for 0.5 seconds, check Mass Air Flow Sensor. Check the harness continuity at MAFS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.

If the GREEN LED flashes 4 times for 0.2 seconds 3 times, check the ignition signal. Check the harness continuity when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.

Hope this helps...
__________________

Well the P0300 code has nothing to do with your O2 sensors just a heads up.

P0300: Random/Multiple Cylinder Misfire Detected

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crankshaft position (CKP) sensor (POS) signal to vary, Powertrain Control Module (PCM) or Electronic Control Module (ECM) can determine that a misfire is occurring.

Causes:
- Improper spark plug
- Insufficient compression
- Incorrect fuel pressure
- The injector circuit is open or shorted
- Fuel injectors may be faulty
- Intake air leak
- The ignition signal circuit is open or shorted

Solutions:
- Perform Injector Service
- Replace Spark Plugs
- Replace Injectors
- Replace Ignition Coils

P0135: O2 Sensor Heated Circuit Malfunction Bank 1 Sensor 1

The front heated oxygen sensor (or sensor 1) is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the ECM. The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.

Causes:
- Harness or connectors (The sensor circuit is open or shorted)
- Front Heated oxygen sensor (Bank 1) may be faulty

Solutions:
Replacing the O2 Sensor 1 usually takes care of the problem

service manual.
Code Description Possible Cause
0 ECU / ECU signal No signal to ECU
1 Oxygen sensor circuit Oxygen sensor or circuit, ECU
2 Oxygen sensor circuit Oxygen sensor or circuit, ECU
3 MAP sensor circuit Map sensor circuit
4 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
5 MAP sensor circuit MAP sensor or circuit, mechanical
problem
6 ECT sensor circuit ECT sensor or circuit, automatic
transaxle control unit
7 TPS / Angle Sensor TPS sensor or circuit, automatic
transaxle control unit
8 CKP sensor / engine speed (RPM) Crank angle sensor or circuit, ECU
sensor
9 CMP sensor CMP sensor or circuit
10 IAT sensor IAT sensor or circuit
11 Idle Mixture Adjuster Sensor Idle mixture adjuster sensor or
circuit
12 EGR system fault No EGR action, faulty EGR valve
13 BARO sensor circuit BARO sensor or circuit
14 Idle Air Control valve circuit / ECU Open or shorted out ignition signal
circuit / No signal to ECU
15 Ignition Output signal Open or shorted ignition output
signal circuit
16 Fuel Injector Circuit Open or shorted fuel injector
circuit
17 VSS circuit VSS sensor or circuit
18 Ignition Timing Adjuster Open or shorted signal circuit
19 A/T Lock-up control solenoid Open or shorted signal circuit,
Lock-up control solenoid lock-up solenoid
20 Electrical Load Detector / Sensor Electrical load detector or circuit
Honda/Acura
Fault Code Definitions (21 - 59)
Chapter 3 22
Code Description Possible Cause
21 Spool Solenoid Valve Open or shorted signal circuit,
spool solenoid valve
22 Valve Timing Electronic Oil Open or shorted signal circuit,
pressure switch valve timing oil pressure switch
23 Knock sensor circuit Knock sensor or circuit
30 AT / ECU communication signal A AT control unit, ECU
31 AT / ECU communication signal B AT control unit, ECU
35 Traction control / ECU / signal Traction control module, ECU
36 Traction control / ECU / signal Traction control module, ECU
41 Oxygen sensor heater - left side Oxygen sensor / heater or circuit
42 Oxygen sensor heater - right side Oxygen sensor / heater or circuit
43 Fuel Supply system - left side Oxygen sensor or circuit, fuel
system
44 Fuel Supply system - right side Oxygen sensor or circuit, fuel
system
45 Fuel metering - left side Injector control circuit, incorrect
fuel metering
46 Fuel metering - right side Injector control circuit, incorrect
fuel metering
48 Heated oxygen sensor Oxygen sensor or circuit
53 Right Knock Sensor Right knock sensor or circuit
54 CKP sensor 2 CKP sensor 2 or circuit
59 CMP sensor 2 CMP sensor 2 or circuit

my mercury mountaineer will barely move and it is loud as ever what could this be