P0043 - OBD Trouble Code
OBD Code P0043 HO2S Heater Control Circuit Low B1S3
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If you feel sudden drop in the engine
performance and continuous stalling and hard idles along with flashing of check
engine lights on the dashboard, this may be an indication of OBD Code P0043
being stored in the PCM/ECM.
P0043 stands for low circuit voltage for
the heated oxygen sensor bank 1 sensor 3. This code can be seen with P0044 and
P0042.
Learn More About OBD Error Code P0043
The definition of P0043 is low voltage for the heater
control circuit. P0043 indicates that the car’s ECU has detected lower than
expected voltage and has triggered a warning light.
PCM (Powertrain Control Module) takes inputs form
Heated Oxygen Sensor to determine oxygen content in the exhaust system. Bank 1,
sensor 3 refers to the third sensor back on bank 1. Bank 1 is the side of the
engine that contains the #1 cylinder. This information is mainly used to
monitor the performance of the catalytic converter which reduces the emissions
on cold start-up. The PCM continuously monitors the heater circuits for
abnormalities. The Oxygen sensor heater can be controlled in one of two ways
depending on the make of the car. One way is that the PCM directly controls the
voltage feed to the heater either directly or via a HO2S relay or would be a
fused 12-volt battery that feeds to the heater element anytime the ignition is
on and the control of the heater is done by a driver in the PCM. It’s important
to find out which way is used to correctly diagnose this problem and to know as
to why the Code P0043 is being set in the PCM.
What
causes the problem of Heater Circuit Control Low (B1 S3)?
- Failed Bank 1 Sensor 3
- Short/open wiring problem
- High resistance and poor electrical connections
- ECU error
Replace/Repair These Parts To Fix OBD Code P0043
- Heated Oxygen
Sensor - The inadequate heating
of the oxygen sensor immediately makes the ECM to go into failsafe mode due to
failure of the fuel delivery system, and engine control module. Replace faulty
sensors immediately.
- Heated Oxygen
Sensor Harness -
OBD Error Code P0043 may also occur if the sensor harness is damaged leading
improper fuel supply causing improper engine performance. It is advised the
replace with the new one. Buy quality auto parts from us.
- Heated Oxygen
Sensor Connector -
A faulty Oxygen Sensor Connector can will not be able to read the correct
volume of air entering the engine. Replace your old/damaged connectors now.
- Heater Circuit Fuse - Damaged Heater Circuit Fuse can
result in improper or complete failure of the heater circuit. Visit us for
quality fuses and parts.
- Engine Control
Module -
ECM faults can store and display wrong OBD Code which can result in wrong
diagnosis. Thus, replace the damaged components now.
- Powertrain Control
Module -
PCM issues directly affects the engine control and transmission control module.
Thus, replace faulty components now.
- Catalytic Converter - Sometimes catalytic converters
can overheat and become faulty. Replace your old catalytic converter now!
- Diagnostic Tool - Find wide range of
diagnostic tools to detect and correct the OBD code error.
- Exhaust System - Replace damaged exhaust parts
immediately as a damaged one hampers the fuel economy and thus the performance.
Symptoms Of OBD Error Code P0043
If the Engine Control Unit detects low on the
heater control circuit for bank1 sensor 3, it will immediately flash Check
Engine Light on the dashboard. In rare cases, the car may also run poorly and
see increased fuel consumption.
How To Correct P0043 HO2S Heater Control Circuit Low B1S3
- Replace Bank 1 sensor 3
- Repair/replace open or short in the wiring
- Bank 1 Sensor 3 fuse replacement
- Replacement of ECU
Easy Diagnosis Of Engine Error OBD Code P0043
- Install
a scan tool in vehicles OBD-II port to check if P0043 is present or not.
- Freeze
frame data and test drive to check if the code reappears under same conditions.
- If
the Check Engine Light returns upon test, then the code is confirmed.
- Performs
a visual inspection of wiring and bank 1 sensor 3 for any damage, breaks, or
shorted wiring.
- Check
for the voltage of Bank 1 sensor 3 and make sure it is not excessively low. If
low voltage is confirmed, bank 1 sensor 3 is faulty.
- A
diagnostic of the ECU will be performed, if the voltage is not low and sensors
are fine.
Common
mistakes when diagnosing the P0043 code
P0043
is an uncommon code and following all diagnostic steps is important so nothing
is overlooked. Oxygen sensors should be properly examined and replaced, if
faulty. Always confirm low voltage for oxygen sensor bank 1 sensor 3 before any
replacement is performed and avoid going to the ECU straightaway.