P20A5 code meaning
Reductant Purge Control Valve A Stuck Closed
Powertrain system Generic code P20xx codes Check engine light
What P20A5 means
Stuck closed is the failure in which the purge valve does not switch to the reverse position when the system wants to empty the line. For the CNRB engine of the 2014 Touareg, Volkswagen bases P20A5 on the pressure difference between the start of the pressure reduction and the current value. Ford reports the code on 6.7 L diesel Super Duty trucks of model years 2023 to 2025, F-650/F-750 included: TSB 24-2055, 24-2379 and 25-2032 trace an illuminated MIL with P20A5 to a software issue of the glow dosing module, shown in the scan tool as secondary OBD control module, and cure it by reprogramming; driving is not affected. On other vehicles a jammed valve or a blocked return line is the real cause. P20A4 is the reverse case. A line left full can freeze and crack in winter.
P20A5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.3 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P20A5
- MIL on, often found after a shutdown cycle
- No change in driveability (Ford software case)
- Frost damage to line or injector if a real valve fault persists
Common causes of P20A5
- Most likelyControl module software (Ford 6.7 L, reprogram the glow dosing module)
- PossibleValve jammed in the delivery position by crystallized DEF
- PossibleReturn line to the tank kinked or blocked
- Less likelyDEF pressure sensor frozen at one value
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant purge valve
What each part of P20A5 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. |
| A5 | The exact fault in that area. |
What to do next
- Note P20A5 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 P20A5
What does P20A5 mean?
P20A5 means "Reductant Purge Control Valve A Stuck Closed". Stuck closed is the failure in which the purge valve does not switch to the reverse position when the system wants to empty the line. It is a generic code, so it means the same on every make.
Is it safe to drive with P20A5?
Drive gently and only to a workshop. With P20A5 the car can go into limp mode (reduced power) to protect itself.
Will P20A5 fail an emissions test?
Yes, it can. P20A5 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 P20A5 to fix?
Difficulty: hard. A typical repair takes 0.3 to 3 hours of work. This is a job for a workshop.
Will P20A5 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.