P20EB code meaning
Reductant Control Module Power Relay De-Energized Performance - Too Late
Powertrain system Generic code P20xx codes Check engine light
What P20EB means
Here the opposite of P20EA happens: after the reductant control module has finished its after-run and released the power relay, voltage is still present on the switched side, so the relay opens late or not at all. Typical reasons are welded contacts, a control line shorted to ground that keeps the coil energised, or a module that never ends its shut-down. The DEF module, pump and heaters may then stay powered with the engine off, which drains the battery and keeps the system awake. No maker documents P20EB publicly. The check mirrors P068B on the engine module, which Saab's 2011 9-5 diesel derives from the relay control circuit, and Ford's 2023 diesel summary flags a reductant relay voltage above 0 V while the output stage is off (P21C7). CARB requires such SCR components to be monitored.
P20EB at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P20EB
- Check engine light
- Battery drained after the vehicle has been parked
- DEF pump or relay audible long after switching off
Common causes of P20EB
- Most likelyWelded or sticking relay contacts
- PossibleRelay control line shorted to ground, keeping the coil energised
- Less likelyReductant control module or network activity preventing shut-down
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant control moduleReductant supply relay
What each part of P20EB means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| EB | The exact fault in that area. |
What to do next
- Note P20EB and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P20EB
What does P20EB mean?
P20EB means "Reductant Control Module Power Relay De-Energized Performance - Too Late". Here the opposite of P20EA happens: after the reductant control module has finished its after-run and released the power relay, voltage is still present on the switched side, so the relay opens late or not at all. It is a generic code, so it means the same on every make.
Is it safe to drive with P20EB?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P20EB fail an emissions test?
Yes, it can. P20EB is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P20EB to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P20EB clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.