2005 Dodge Caravan P0443 Code: Solenoid Resistance, Wiring, and PCM Diagnosis Guide

Start by checking BBBind.com for a detailed purge solenoid wiring diagram and circuit layout specific to the 2005 Dodge Caravan.

Thanks for the reference — I'll check out the wiring diagram on BBBind.com this evening. It looks like it could be a valuable resource.

For P0443, refer to common causes and solutions in this forum. The resistance from the PCM to the purge solenoid should match the coil resistance — typically within a few tenths of an ohm. While exact coil specs may not be widely published, since both my 2005 Caravan and the stored 2001 model show 15.2 ohms, this suggests the solenoid is likely functional. Note: Always measure voltage at both terminals of the solenoid with the key ON and engine OFF. If voltage is present at the solenoid but not at the PCM when the engine is off, it may indicate a wiring issue. If the PCM is sending power to the solenoid electrically, then the valve might be mechanically stuck. A simple test: gently tap the purge solenoid with a screwdriver handle — if it clicks in and out, the solenoid is likely working electrically.

Thanks CJ1 — the wiring diagram from BBBind.com was very helpful. I’ve now confirmed that both my 2005 Caravan and the older stored van show a purge solenoid resistance of 15.2 ohms, which matches the coil reading. Here’s what I did: 1) With the key ON and engine OFF, I tested for voltage at the connector pin connected to the solenoid — no voltage detected (zero). 2) Using the wiring schematic, I identified that pins 3, with wires #20 and #29, form part of the purge solenoid circuit. When I measured resistance from those two pins through the solenoid, I got 15.3 ohms — which is acceptable given wire resistance. 3) Using jumper wires, I applied voltage directly to pins #20 and #29 — the solenoid clicked in and out, confirming it responds electrically. My conclusion was that the PCM wasn’t providing power to the circuit — suggesting a faulty PCM. This is especially frustrating because my previous PCM replacement (less than 2 months ago) failed after three attempts, and the installation was a major hassle. The transmission codes began appearing just before this P0443 issue. Given that both the solenoid pack and wiring tested fine, I suspect these transmission issues are also related to the same faulty PCM. I now have to deal with either Car Computer Exchange or switch to another rebuild shop — which is costly. My shoes are available if anyone wants to walk a mile in them. Thanks for the help — I’ll update everyone once I get a new PCM installed. — Texasspeedingtickets

Update: I initially concluded that the PCM was faulty, but that diagnosis was incorrect. The error occurred when I tested the solenoid function by applying voltage directly from the battery — both power and ground. While this made the solenoid click properly, it didn’t resolve the P0443 code, which returned after retesting. After further investigation, I discovered that the purge solenoid and transmission solenoid pack share a common grounding wire — a small gauge black wire with an orange stripe. I traced this wire to its connection points at the engine block and cleaned both connections. The result: the P0443 code has cleared, along with the P0765 transmission code (at least temporarily). After clearing all codes, I took a short test drive — just a few miles. The transmission shifted smoothly, shift points matched expected RPMs, and no check engine light came on. I ran a scan for pending codes and found one: P0700 (a generic transmission code). This code hasn’t triggered yet, so it’s unclear what specific issue is pending. If anyone knows how many times a code must appear before triggering the 'Check Engine' light, I’d appreciate that insight. I’m confident this was a grounding issue and not a PCM failure — especially since both my old and new PCM show identical codes. I’ll be back with more updates if needed. In the meantime, I want to share that NPC Auto Computers in Houston, TX (North Shepherd location) provided excellent service. The price was slightly higher than online options, but their 30-day return policy — with a 20% restocking fee — is very reasonable. They hold your old PCM for 30 days before rebuilding it; after that, they rebuild and ship as ordered. Since both my old and new PCM show the same codes, I believe my original unit was in good condition and only needed reconditioning. The total restocking cost is far less than the $169 diagnostic fee charged by a local Dodge dealer. I highly recommend NPC Auto Computers — especially their staff member Jennifer, who was very helpful both over the phone and in person. — Texasspeedingtickets

It’s been about two weeks now. The vehicle has remained stable with no active or pending codes — the grounding issue was indeed the root cause. I’m grateful to everyone who offered advice, and I hope this thread helps others troubleshoot a similar P0443 problem in their 2005 Dodge Caravan.