You can usually drive short distances, but watch the temperature gauge closely. If it climbs at idle, with the A/C on, in traffic, or towing, stop and let it cool — repeated overheating can warp the head or fail the head gasket. Get it fixed promptly. P0693 is a powertrain code meaning the engine computer (PCM) detected a LOW electrical condition — typically a short to ground or a stuck-low driver — on the Fan 2 control circuit, the wire it uses to switch the second (usually high-speed) radiator cooling fan relay. It is the fault-side counterpart to P0694 (Fan 2 circuit high) and the fan-2 sibling of P0691 (Fan 1 low).
What P0693 means
Many dual-fan and two-speed cooling systems give the PCM two separate control circuits: one for the low-speed fan relay (the Fan 1 codes) and one for the high-speed or second fan relay (the Fan 2 codes). On Chrysler and Jeep two-speed setups the PCM supplies a ground to the LOW fan relay for base cooling, then grounds the HIGH (Fan 2) relay when extra airflow is needed, deciding this from engine coolant temperature, transmission oil temperature, and A/C refrigerant pressure. The PCM watches the voltage on each control wire, and P0693 sets when the Fan 2 line reads LOW when it should not — the classic signature of a short to ground in the wiring, a shorted or stuck relay coil, or a failed low-side driver inside the PCM. Because Fan 2 usually carries the high-speed stage, a fault here means the fan may not spin up to full cooling under load even if the low-speed stage still works, so overheating risk appears when demand is highest — idling with the A/C on, crawling in traffic, towing, or hot weather.
Symptoms
- Check Engine light on, frequently stored with other fan codes such as P0691, P0692, or P0694
- Engine coolant temperature climbing toward the hot zone at idle, in slow traffic, or while towing
- Cooling fan not reaching high speed when it should, even though the low-speed stage may still run
- A/C performance dropping off at idle because condenser airflow is reduced
- Temperature gauge that reads normal at highway speed (ram air) but rises when the vehicle stops
- In some cases the fan stuck full-on or not responding to commands, depending on where the short lies
Common causes
- Short to ground in the Fan 2 control wire between the PCM and the fan relay or fan module
- Shorted or internally failed high-speed / Fan 2 relay coil dragging the control line low
- Chafed, pinched, or melted harness near the radiator, fan shroud, or hot engine components
- Corroded, water-intruded, or backed-out terminals at the relay or PCM connector
- Poor connector fit at the fan relay box (Chrysler/Jeep integrated power module) letting moisture in
- Damaged fan relay socket or power-distribution center contacts feeding the Fan 2 circuit
- Failed low-side driver inside the PCM on the Fan 2 output (least common — confirm wiring first)
Severity & driving advice
Severity: Moderate — The high-speed fan stage may not run, so the engine can overheat at idle, in traffic, or while towing even if it stays cool on the highway.
Can I drive? You can usually drive short distances, but watch the temperature gauge closely. If it climbs at idle, with the A/C on, in traffic, or towing, stop and let it cool — repeated overheating can warp the head or fail the head gasket. Get it fixed promptly.
Diagnostic approach
- Read all codes and freeze-frame first — Pull every stored DTC and note the companions. Fan 1 codes (P0691 low, P0692 high) point at the low-speed control circuit, while P0693 and P0694 both cover the Fan 2 (high-speed / second fan) circuit — P0693 is the low fault, P0694 the high. Seeing several fan codes together often points at a shared connector, ground, or the relay box rather than a single wire.
- Confirm the fan strategy on your vehicle — Identify whether the system is a true two-fan setup or a single fan run at two speeds through two relays. On the Chrysler/Jeep two-speed design the PCM grounds a LOW relay for base cooling and grounds the HIGH (Fan 2) relay for extra airflow, so on these platforms P0693 is the high-speed control side. Knowing this tells you which relay and which wire to probe.
- Command the fan and watch behavior — With a scan tool, actuate the high-speed / Fan 2 output (or run the engine up to fan-on temperature with the A/C on) and observe. If the low-speed stage runs but the fan never ramps to high, that agrees with a Fan 2 control-circuit fault. A fan that runs full-on constantly can indicate a hard short to ground on the control line.
- Inspect the Fan 2 control wiring and connectors — Trace the control wire from the PCM to the Fan 2 / high-speed relay. Look for chafing where the harness passes the radiator support, fan shroud, or hot exhaust, and check the relay-box and PCM connectors for green corrosion, spread terminals, or water intrusion — a common trigger on Chrysler and Jeep integrated power modules. Repair damaged insulation before further testing.
- Check the control circuit for a short to ground — Disconnect the Fan 2 relay and the PCM, then measure resistance from the control wire to a good chassis ground. A very low reading (near 0 ohms) confirms the short to ground that sets P0693. An open or high resistance instead points toward P0694 (circuit high). Wiggle the harness while measuring to catch an intermittent short.
- Test the relay and its socket — Measure the Fan 2 / high-speed relay coil resistance and compare it against a known-good identical relay; an internally shorted coil can pull the control line low. Swap in a good relay as a quick check, and inspect the relay socket or power-distribution contacts for burning or spread terminals.
- Verify the PCM driver last — Only after the wiring, connectors, relay, and grounds test clean should you suspect the PCM's Fan 2 low-side driver. Confirm the PCM has good power and grounds, then back-probe the control output while commanding the fan; a driver that will not release the circuit from ground, with wiring proven good, indicates an internal PCM fault, which is the least common and most expensive cause.
FAQ
Can I keep driving with a P0693 code?
Cautiously and briefly. The Fan 2 circuit usually runs the high-speed cooling stage, so at highway speed ram air may keep temperatures fine, but the engine can overheat at idle, in slow traffic, with the A/C on, or while towing. Keep an eye on the temperature gauge and shut the engine off if it climbs toward hot, because repeated overheating risks expensive engine damage.
What is the difference between P0693 and P0691?
They cover different fan control circuits. P0691 is Fan 1 Control Circuit Low — the low-speed fan relay control wire reading low. P0693 is Fan 2 Control Circuit Low — the second or high-speed fan relay control wire reading low. Both describe a short-to-ground / stuck-low condition, but on different stages of the cooling fan system.
How is P0693 different from P0481?
P0481 is a broader Fan 2 (Fan Control) circuit malfunction code that flags a general problem with the fan-2 control circuit without pinning down the electrical direction. P0693 is more specific: it says the Fan 2 control circuit is reading LOW, which usually means a short to ground or a stuck-low driver. If you see both, treat P0693 as the more detailed description of the same fan-2 control fault.
Does P0693 mean my cooling fan is bad?
Not necessarily. P0693 is about the control circuit the PCM uses to switch the Fan 2 relay, not the fan motor itself. The real cause is most often a shorted or chafed control wire, a corroded connector, or a failed high-speed relay. The fan motor and the higher-current power side are usually fine, though it is worth confirming the fan spins freely once the circuit is repaired.
Why does my engine only overheat at idle or in traffic with P0693?
At speed, air is forced through the radiator, so the engine can stay cool even without the high-speed fan. When you stop or slow down, that ram air disappears and the cooling system depends on the fan pulling air through. If P0693 has knocked out the high-speed (Fan 2) stage, temperatures climb exactly in those low-airflow situations — idling, crawling in traffic, running the A/C, or towing.