P20D0 Exhaust gas injector A stuck closed
OBD2 Error Codes

P20D0 Exhaust gas injector A stuck closed

P20D0 Exhaust gas injector A stuck closed

OBD-II DTC Datasheet

Aftertreatment fuel injector A stuck closed

What does this mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code and applies to many OBD-II vehicles (1996 and newer). This may include but is not limited to Mercedes Benz, Sprinter, GMC, Chevrolet, Ford, etc. While general, the exact repair steps may vary depending on the model year, make, model and transmission configuration.

If your diesel vehicle has stored the code P20D0, it means that the powertrain control module (PCM) has detected an abnormal voltage that is outside the normal range of expected values ​​on the control circuit for the aftertreatment system fuel injector labeled A. the fact that several nozzles of the reducing agent are used.

An Exhaust Aftertreatment System (also called a Selective Catalyst Recovery System) is used to enhance the capabilities of the catalytic exhaust gas system. It can consist of one or more of these elements; diesel oxidation catalyst, particulate filter, reducing agent injection system, ammonia slip catalyst and nitrogen oxide (NOx) trap.

Among other things, exhaust gas aftertreatment systems (EAS) are responsible for injecting a reductant / diesel engine fluid (DEF) compound into the exhaust gases upstream of the particulate filter, NOx trap and / or catalytic converter via an automated fluid storage. and injection system. The addition of DEF to the catalytic system extends the life of the filter element and reduces emissions of harmful exhaust gases into the atmosphere.

EAS systems and catalysts are monitored and controlled by either the PCM or a stand-alone controller (which interacts with the PCM). The controller monitors the O2, NOx and exhaust gas temperature sensors (as well as other inputs) to determine the appropriate timing for the DEF (reductant) injection. DEF must be injected at the correct time and to the exact extent to keep the exhaust gas temperature within acceptable parameters and to optimize the filtration of pollutants.

If the PCM detects an abnormal voltage that is outside the normal expected range on the control circuit for the EAS fuel injector, a P20D0 code will be stored and a malfunction indicator lamp may illuminate.

P20D0 Exhaust gas injector A stuck closed

What is the severity of this DTC?

A stored P20D0 code should be treated as serious and rectified as soon as possible. The EAS system can be damaged as a result of conditions that contributed to the persistence of the P20D0 code.

What are some of the symptoms of the code?

Symptoms of a P20D0 trouble code may include:

  • Reduced engine performance
  • Excessive black smoke from vehicle exhaust
  • Decreased fuel efficiency
  • Other codes related to EAS / SCR

What are some of the common causes for the code?

Reasons for this code may include:

  • Defective EAS fuel injector
  • Open or short circuit in the EAS fuel injection control circuit
  • Insufficient DEF in the EAS reservoir
  • Bad EAS / PCM controller or programming error

What are some steps to troubleshoot the P20D0?

Diagnosing a P20D0 code will require a diagnostic scanner, digital volt / ohmmeter (DVOM), and vehicle-specific diagnostic source.

Search for a Technical Service Bulletin (TSB) that matches the year of manufacture, make and model of the vehicle; as well as engine displacement, stored codes, and detected symptoms can provide useful diagnostic information.

I like to start my diagnosis with a visual inspection of the EAS wiring harnesses and connectors. Burnt or damaged wiring and / or connectors must be repaired or replaced before proceeding.

I would proceed by connecting the scanner to the vehicle's diagnostic connector and retrieving all stored codes and associated freeze frame data. Make a note of this information before clearing codes. Test drive the vehicle until the PCM enters readiness mode or the code is cleared.

If the PCM enters ready mode during this time, the code is intermittent and can be much more difficult to diagnose. If so, the conditions that contributed to the retention of the code may need to worsen before an accurate diagnosis can be made.

If the code is reset immediately, the next diagnostic step will require searching the vehicle information source for diagnostic block diagrams, connector pinouts, connector faces, and component test procedures and specifications. You can also use your vehicle information source to determine the exact location of the A EAS fuel injector.

Use the DVOM to check (voltage drop) the power supply of the EAS control system. Check fuses with a loaded circuit to avoid misdiagnosis. If proper power (battery voltage) and ground circuits are found, use a scanner to activate the EAS fuel injector (solenoid) and check the control circuit output voltage. If the voltage is insufficient, suspect the controller is defective or has a programming error.

If the voltage output circuit is within specifications, use the DVOM to test the EAS fuel injector in question. If the injector does not meet manufacturer's specifications, suspect that it is out of order.

  • The EAS fuel injector is simply a solenoid-based injector that sprays reductant fluid into the exhaust pipe.
  • Do Not Forget Ground Loops When Testing Voltage Drop

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Need more help with a P20D0 code?

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.

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