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Discussion Starter · #1 ·
Hello,
I'm new in brand, i scan my and i got the 1128 code, i want to help me some one to find a reason to eliminate the problems

Thank's !
 

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Hey I get that f%$king code too all the time. . . . . It is the O2 sensor 1st bank (precat) and thus far I have tried the following

1) Replaced O2 sensor
2) Replaced MAF sensor
3) Checked grounds
4) Took it to a hyundai dealership. . . . . even they couldn't tell me why I keep getting the code. . . . but the tech who did the testing said that all the readings from ALL of the cars sensor's (he checked them all to be sure that it wasn't being triped because of another sensor somehow)

Anyway this is a TSB from Hyundai regarding it:
Global Service Way
DESCRIPTION:
The Powertrain Control Module (PCM) on Hyundai OBD II vehicles (all 1996 and later models) can adjust the engine Air to Fuel (A/F) ratio to compensate for variations in operating conditions. This adjustment only takes place during "Closed Loop" operation.

The PCM uses input from the following components to determine the amount of fuel to deliver:
Oxygen sensors
Air flow sensor
Coolant temperature sensor
Intake air temperature sensor
Throttle position sensor
Engine speed sensor

The ability to adjust the A/F ratio enables the PCM to compensate for engine, fuel and sensor variations as well as temperature, altitude and humidity. This enables the vehicle to maintain a stoichiometric (14.7 to 1) A/F ratio that will ensure optimal engine performance and minimal emissions.

Since the PCM can change the A/F ratio to compensate for a wide range of conditions, an indicator is needed to identify that a compensation has been made. Fuel Trim values shown on the HDS scan tool are the primary indicator that an adjustment in fuel delivery has taken place.

The scan tool displays the PCM's A/F ratio compensation as "Short Term" Fuel Trim (ST TRIM), Long Term Fuel Trim (LT TRIM), and "Oxygen Sensor" Trim (TRIM B1 S1 and B1 S2). The most beneficial diagnostic information comes from "Short Term" Fuel Trim and "Long Term" Fuel Trim.
"Short Term" Fuel Trim (ST TRIM):
"Short Term" Fuel Trim is the value that represents the quick small changes the PCM makes to the A/F ratio.
On a Sonata, the PCM continuously responds to the signals from the oxygen sensors to maintain the 14.7 to 1 A/F ratio by increasing or decreasing fuel delivery.
On Accent, Elantra and Tiburon, the "Short Term" Fuel Trim indicates the amount of correction at idle and low rpm/load.
"Short Term" Fuel Trim values range from -25% to +25%.
"Short Term" Fuel Trim values are positive when the PCM is increasing fuel delivery, negative when the PCM is decreasing fuel delivery. "Short Term" Fuel Trim may read "0.0" for brief periods during transition from positive to negative (or negative to positive) operation. If the "Short Term" Fuel Trim reads "0.0" for longer periods, it may indicate that the vehicle is in open loop.
On a Sonata, the "Short Term" Fuel Trim values are not retained in the PCM memory when the ignition is turned off.
"Long Term" Fuel Trim (LT TRIM):
On a Sonata, "Long Term" Fuel Trim values change to compensate when the "Short Term" Fuel Trim has reached its limit in one direction and is unable to maintain the 14.7 to 1 A/F ratio.
On Accent, Elantra and Tiburon vehicles, the "Long Term" Fuel Trim indicates the amount of correction at high rpm/load.
The "Long Term" Fuel Trim correction range is -25% to +25%. Exceeding the -20% to +20% range will set a code on an Accent, Elantra and Tiburon. Sonata vehicles will set a code when the -12.5% to +12.5% range is exceeded.
On a Sonata, a one digit change of the "Long Term" Fuel Trim value is roughly the equivalent of one entire "Short Term" Fuel Trim range. For example: when the "Short Term" Fuel Trim reaches its limit, the "Long Term" Fuel Trim moves one digit. This process repeats until the A/F ratio returns to 14.7 to 1 or the "Long Term" Fuel Trim correction range limit has been exceeded.
There is a preprogrammed "Long Term" Fuel Trim correction range that is acceptable for normal operation. When the "Long Term" Fuel Trim exceeds this range in two driving cycles, the vehicle will set a diagnostic code (DTC), which will illuminate the check engine light.
"Long Term" Fuel Trim values are retained in the PCM's memory when the ignition is turned off. This allows the vehicle to "learn" a new fuel delivery schedule, which is "fine tuned" for optimal performance.
Oxygen Sensor Trim (TRIM B1 S1 And TRIM B1 S2):
Oxygen Sensor Trim is the PCM's response value to each individual oxygen sensor input. This value should change similar to the "Short Term" Fuel Trim values and is not used for diagnostic purposes on Hyundai vehicles.
FUEL TRIM DIAGNOSTIC CODES:

A Fuel Trim diagnostic code will set when Fuel Trim values exceed programmed limits due to either "Rich" or "Lean" operating conditions. The "Long Term" or "Short Term" Fuel Trim numbers stored in the "Freeze Frame" data will indicate if the PCM was increasing or decreasing fuel delivery when the code was set.

A PCM that is increasing fuel delivery (to compensate for a "Lean" condition) will have a positive (+) "Long Term" Fuel Trim number. A PCM that is decreasing fuel delivery (to compensate for a "Rich" condition) will have a negative (-) "Long Term" Fuel Trim number.
Accent, Elantra And Tiburon Fuel Trim Codes:
The "Long Term" Fuel Trim correction range is -25% to +25% on Accent, Elantra and Tiburon. If the "Long Term" Fuel Trim value exceeds -20% to +20% in two consecutive trips a code will be stored in the PCM.
P1123 and P1124
are set at idle, low load and low engine speed operation. Codes set in these operating conditions are sometimes referred to asadditive
Fuel Trim correction codes.
NOTE
These codes are set when engine speed is less than approximately 1,000 rpm and the air flow sensor reading is less than 5 grams/sec.

P1127 and P1128 are set at moderate to high engine load and engine speed operation. These codes are sometimes called multiplicative
Fuel Trim correction codes.
ACCENT, ELANTRA And TIBURON FUEL TRIM CODES
CODE DESCRIPTION CONDITION
P1123
Fuel Trim Rich at Idle
The PCM decreased
fuel delivery at idle to the programmed limit, attempting to compensate for a rich
condition.

P1124
Fuel Trim Lean at Idle
The PCM increased
fuel delivery at idle to the programmed limit, attempting to compensate for a lean
condition.

P1127
Fuel Trim Rich Under Load
The PCM decreased
fuel delivery under load to the programmed limit, attempting to compensate for a rich
condition.

P1128
Fuel Trim Lean Under Load
The PCM increased
fuel delivery under load to the programmed limit, attempting to compensate for a lean
condition.

DTC P1124, P1128, or P0170 (with positive Fuel Trim numbers):

(The PCM is increasing fuel delivery to compensate for a "Lean" condition)
Check for vacuum or unmetered air leaks, concentrating on areas between the air flow sensor and the engine block. Are all the gaskets and hoses properly installed? A vehicle with a vacuum leak will have an air flow sensor reading that is lower than normal at idle (see Air Flow Sensor Table below). Accent, Elantra and Tiburon vehicles with a vacuum leak may also have a low load value.
Check the evaporative emission system. An intermittently sticking or stuck open purge solenoid valve may not set an evaporative code in a 1996 or 1997 SOHC Accent or Sonata, but may set a Fuel Trim code.
Check the air flow sensor calibration. If no vacuum leaks are present and the purge system is functioning properly, compare the air flow sensor reading at idle and at 2500 rpm to the Air Flow Sensor Table below. If readings are out of specification, swap the air flow sensor with a known good unit and re-test.
Check the fuel pressure (for low pressure), fuel volume flow (replace fuel filter if necessary), injector part number, PCM part number and perform the oxygen sensor scan tool test as noted below.
DTC P1123, P1127 or P0170 (with negative Fuel Trim number):

(The PCM is decreasing fuel delivery to compensate for a "Rich" condition)
Check the evaporative emission system. An intermittently sticking or stuck open purge solenoid may not set an evaporative code in a 1996 or 1997 SOHC Accent or Sonata, but may set a Fuel Trim code.
Check the air flow sensor calibration. If no vacuum leaks are present and the purge system is functioning properly, compare the air flow sensor reading at idle and at 2500 rpm to the Air Flow Sensor Table below. If readings are out of specification, swap the air flow sensor with a known good unit and re-test.
Check the fuel pressure (for high pressure), the fuel flow (for a return line restriction), the injector part number, the PCM part number and perform the oxygen sensor scan tool test as noted below.
NOTE
For 1996 Accent SOHC with diagnostic code P1123 only, refer to TSB# 96-36-004 (Powertrain Control Module EPROM Replacement Procedure).

APPROXIMATE AIR FLOW SENSOR VALUES (ENGINE HOT, ACCESSORIES And COOLING FANS OFF)
SONATA V6 SONATA
2.0L ACCENT
SOHC ACCENT GT
(DOHC) ELAN-
TRA
1.8L TIB-
URON
1.8L TIB-
URON
2.0L
Air Flow
(grams/sec)
at Idle
3.9 ± 0.3
3.0 ± 0.25
2.75 ± 0.25
2.9 ± 0.25
2.9 ± 0.25
2.9 ± 0.25
2.9 ± 0.25

Air Flow
(grams/sec)
at 2500 RPM
13.0 ± 0.4
8.5 ± 0.50
8.5 ± 0.50
8.0 ± 0.50
8.3 ± 0.65
9.0 ± 0.25
9.3 ± 0.30


NOTE
The above table is supplied as general reference information. If the Fuel Trim conditions occur at different RPM, compare the air flow sensor reading to a known good vehicle. A "new" vehicle or sensor may read a slightly higher value than normal.
 

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Sorry, didn't all fit. . . . .here is the rest

OXYGEN SENSOR SCAN TOOL TESTING PROCEDURE:

Connect the scan tool
Warm up the vehicle to operating temperature (for at least 3 minutes)
Select vehicle, year, VIN code, etc.
Select "Engine"
Select "Data"
After OBD II data appears, press "N"
Select "Custom Data List"
Select "O2-B1-S1" and "O2-B1-S2" (front and rear oxygen sensors) and ENG RPM if no tachometer is available.
Press "N" and the selected data will appear
While holding the engine speed at 2500 rpm in "Neutral" or "Park" (with no load) observe the front and rear oxygen sensors for approximately one minute. The front oxygen sensor should fluctuate rapidly between 0.095 and 0.995 V. The voltage should read higher than 0.600 V several times and lower than 0.350 V several times. The voltage should never exceed 1.00 V when using the scan tool.If an Accent, Elantra or Tiburon front or rear oxygen sensor reads a fixed value of 0.425 V to 0.500 V, or a Sonata reads a fixed value of 0.010 to 0.080 V, check for an open/shorted oxygen sensor circuit or no output from the sensor.

The scan tool can also be used to check the sensors while the vehicle is being driven. An assistant is needed to perform this procedure. Use the scan tool as set up in the previous test procedure.
While driving in first gear, accelerate so the engine speed is near 4000 rpm. Quickly release the accelerator and observe the readings from both sensors. The sensors should read lean (in the range of 0.20 V down to 0 V) on the scan tool due to the fuel cut-off during deceleration.
While driving in first gear, accelerate hard and observe both sensors. The sensors should read rich (in the range of 0.60 V to 1.0 V) on the scan tool.
 

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Discussion Starter · #4 ·
Thank's

Thank's for information
Were can i buy a book about my car ( Hyundai Accent 2000 )
I want to be a good mechanical engineer :)
 
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