4WD Low Switch Circuit Low
The P2773 code indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the four-wheel drive (4WD) low switch circuit. This switch is typically located on the transfer case and signals when the vehicle is in 4WD Low range. A low circuit voltage suggests a short to ground, a faulty switch, or a wiring issue. This can prevent the 4WD system from engaging or disengaging properly, potentially leaving the vehicle stuck in 4WD Low or unable to enter it.
01. Most Common Causes
- Faulty 4WD low switch
- Short to ground in the switch circuit wiring
- Corroded or damaged connector at the switch
- Internal PCM failure (rare)
02. Symptoms You Will Notice
- 4WD Low indicator light stays on or flashes
- Unable to shift into or out of 4WD Low
- Check Engine Light illuminated
- Vehicle may not shift properly between 4WD modes
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the 4WD low switch and wiring for damage, corrosion, or loose connections.
Step 3: Disconnect the switch and measure resistance; compare to specifications (usually open circuit when not pressed, closed when pressed).
Step 4: Check for voltage at the switch connector with key on; should see 5V reference signal. If not, check for shorts or opens in the wiring.
Step 5: If wiring and switch are good, suspect PCM issue; perform PCM test or reprogram.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code, as the 4WD system may malfunction, potentially leaving you stuck in 4WD Low, which can cause driveline damage at high speeds.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a switch replacement, plus diagnostic time. Wiring repairs may add $100-$200.