Error Code P0078: What It Means & What To Do?
OBD Code P0078 - Exhaust Valve Control Solenoid Circuit B1
The P0078 fault code is defined as
Exhaust Valve Control Solenoid Circuit Bank 1. It is a generic code indicates that
the engine control module has tried to control the Bank 1 exhaust valve control
solenoid and at the same time has found some issue. You can see this code in
addition to P0079 and P0080 codes.
Learn More about OBD Error Code P0078
Oil
pressure as well as an electrical solenoid is used by the exhaust valve control
solenoid to control the position of the exhaust valve. The vehicles which are
new are well equipped with variable valve timing. The opening and closing of
the exhaust valve is adjusted by the engine control module with a motive of
improving fuel consumption and at the same time would make sure to provide
performance to the driver. The PCM would set the P0078 fault code if it
determines that there is some issue with the exhaust control solenoid.
What causes this problem with the Exhaust Valve Control
Solenoid Circuit B1?
- There
can be some faults in the exhaust valve timing control magnet retarder
- You
may experience some issues with the VT solenoid valve like there can be an open
circuit in the solenoid coil.
- There
can be an open or short in wiring
- Some sort
of faults in the engine control module or powertrain control module
- The
car engine may not start
- The
engine oil level/pressure may be low
- The electrical wiring may be loosened up or the connectors in the VVT circuit might be corroded
- The
issue of short to ground
Replace/Repair These Parts To Fix OBD Code P0078
- Valve Timing Solenoid - OBD Error Code P0078 can simply be due to faulty Valve
Timing Solenoid. Replace old and damage components now!
- Engine Control
Module - If
there is any fault detected in the Engine Control Module, it will flash OBD
Code P0078. Replace faulty ECM components now!
- Exhaust Valve Control Solenoid - OBD Code P0078 can flash if the Exhaust Valve Control Solenoid is damaged. You must replace it with a brand new one online with us.
- Powertrain Control Module - Did your mechanic just found out that there is some fault
in the Powertrain Control
Module? Buy top notch PCM parts from us at economical prices.
Symptoms Of OBD Error Code P0078
You
might be thinking that how would you diagnose these problems? We at Parts
Avatar Canada would help you diagnose the major symptoms easily. The P0078
would start producing a check engine light on the dash and would likely cause:
Common Symptoms
- Check
engine light may start
illuminating
- The car
engine may suffer choppy acceleration and poor cruising fuel economy
- Engine
may not start functioning
- The
car engine will usually run fine, but you may start noticing rough idle
- The overall engine performance
- Warning
light of service engine soon may start appearing
How To Correct P0078 Exhaust Valve Control Solenoid Circuit (Bank 1)
- The
car battery may be disconnected. If you want to access the module, then you
must remove the trim panels
- Then
you must disconnect the engine control module connections to remove the module
- Now
the new module should be installed as well as secured. After that the
electrical connections should be connected
- Reconnect
the battery and then connect the charger to maintain the battery charge if
needed. Reinstall the removed access or trim panels
- Program
the engine control module to work with the vehicle for operation with an
approved scan tool or methods
- Disconnect the charger and road test the vehicle for proper operation
However, if you face any issue then you must visit us. We have stocked a wide range of best priced ECM, solenoid, check valve and a lot more to help you out in fixing your car.
Easy Diagnosis Of Engine Error OBD Code P0078
- First
of all, you must check for unplugged harness connections, look if there is any
corrosion or some loose wires to connectors. The harness connectors from
Solenoid and PCM should be unplugged, using a wiring diagram locate the + and -
wires to the solenoid. The solenoid can be ground side or power side
controlled; it all depends upon the application.
- If
you want to determine the power flow in the circuit, then you can check with
factory wiring diagrams. Using a digital volt ohm meter (DVOM) set to the ohms
setting, check for resistance between each end of the wire. An over limit
reading on the DVOM may be an open in the wiring, loose connection or terminal.
- Make
sure that the resistance should be around 1 ohm or less, if there is excessive
resistance there may be corrosion or bad wiring between the solenoid and the
power control module or the engine control module.
- Now
with the electrical harness to the solenoid unplugged, using the DVOM set to
ohms, you should check for resistance between each of the electrical terminals
on the control solenoid itself.
- You
can use the factory specifications or a known good control solenoid if available
to determine if there is excessive resistance in the solenoid. If there is an
over limit or excessive resistance reading on the DVOM, then it means that
there are some faults in the solenoid
- Check
for a short to ground through the control solenoid by putting either DVOM lead
to a known good ground and the other to each terminal on the control solenoid.
If there is resistance present, the solenoid may be shorted internally.
- Intermittent
conditions can prove to be quite a challenge to diagnose and in extreme cases
may have to be allowed to worsen before a correct diagnosis can be made.
Carefully inspect the electrical wiring and connectors for inconsistencies,
including shorted or broken wiring and corroded connector faces
- All
the timing components should be properly aligned and that engine oil level and
engine oil pressure should be within acceptable specifications
- If
all these checks are acceptable, then you must test the system components and
voltage/resistance with the help of manufacturer’s reference voltage and
resistance figures
Common Mistakes When Diagnosing the P0078 Code
The
intermittent issues as well as many other factors play a very important role
while diagnosing a check engine light. You must follow all the steps mentioned
above in proper order and should not hurry in getting any car part replaced
without getting it inspected properly and then you will surely be able to correct
the issue. The most common mistake which people make is by replacing the
solenoid before performing proper diagnosis.