P3428 code meaning
Cylinder 4 Deactivation/Intake Valve Control Circuit High
Powertrain system Generic code P34xx codes Check engine light
What P3428 means
P3428 means the wire that switches cylinder 4's deactivation solenoid is tied to voltage. GM's bulletin 20-NA-038 lists cylinders 1, 4, 6 and 7 as the ones its AFM V8s switch to V4 mode, which makes cylinder 4 a standard candidate. In the 2019 documents for L84, L86 and the Corvette LT4, GM judges the circuit with the low-side stage switched on: a supply path of less than half an ohm counts as a short, and 20 bad results within 25 produce a Type B entry and the lamp after two trips. Because the low-side stage sinks the current, a line stuck at battery voltage can push the output into overcurrent, so after repair the module should be checked too. P3427 is the short to ground, P3425 the open. The truck or car keeps all cylinders running.
P3428 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P3428
- Check engine lamp on
- No V4 or reduced-cylinder operation
Common causes of P3428
- Most likelyCylinder 4 control wire shorted to a 12 V feed
- PossibleLow-resistance winding in the cylinder 4 solenoid
- Less likelyOverloaded output stage in the engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder deactivation solenoidWiring harnessECM
What each part of P3428 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 3 | Mixed range: generic and manufacturer-specific codes. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 28 | The exact fault in that area. |
What to do next
- Note P3428 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 P3428
What does P3428 mean?
P3428 means "Cylinder 4 Deactivation/Intake Valve Control Circuit High". P3428 means the wire that switches cylinder 4's deactivation solenoid is tied to voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with P3428?
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 P3428 fail an emissions test?
Yes, it can. P3428 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 P3428 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P3428 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.