P05C7 code meaning
Economy Mode Switch Circuit/Open
What P05C7 means
The economy mode switch selects a fuel-saving mode (flatter pedal map, earlier upshifts, sometimes reduced A/C). It is usually a resistor ladder with 5 V reference read by the engine module; CARB names a driver-selectable eco mode as an off-cycle technology whose use must be counted. GM reports the same switch with its own codes P159F/P15A0, type B with warning lamp after two trips; P05C7–P05CA appear in no manufacturer document available to us. P05C7 means the switch circuit is open; eco mode cannot be selected and the vehicle runs in normal mode.
P05C7 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P05C7
- Eco mode not selectable
- Eco indicator not working
- Vehicle runs in normal mode
Common causes of P05C7
- Most likelyWire or connector to the switch open
- PossibleSwitch faulty (resistor ladder or contact)
- PossibleConnector loose after console work
- Less likelyModule input
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Economy mode switchSwitch wiringEngine control module
What each part of P05C7 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| C7 | The exact fault in that area. |
What to do next
- Note P05C7 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 P05C7
What does P05C7 mean?
P05C7 means "Economy Mode Switch Circuit/Open". The economy mode switch selects a fuel-saving mode (flatter pedal map, earlier upshifts, sometimes reduced A/C). It is a generic code, so it means the same on every make.
Is it safe to drive with P05C7?
P05C7 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P05C7 fail an emissions test?
P05C7 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P05C7 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P05C7 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.