JamesTheScot
New Member
- Joined
- Nov 19, 2020
- Messages
- 2
- Reaction score
- 0
- Points
- 1
- Location
- Kentucky, USA
- Vehicle Year
- 2002
- Make / Model
- Ford Ranger
- Transmission
- Automatic
Hey everyone. My son showed up last night in a tow truck with the ‘02 Ranger.
He was leaving a buddy’s house and it would not start. It had been running fine prior to that. Except that he had just replaced the battery about 24 hours prior due to a low battery that tested bad. Not sure if it could be related, but there it is.
I checked out the Ranger some. It cranks just fine. Strong with no dragging. But I noticed that the check engine light isn’t coming on at key on and engine off. Also, the tachometer isn’t moving even a twitch while the starter cranks the motor.
I’ve tried to do some troubleshooting online which always points in the direction of a PCM issue rather than a spark or fuel issue. I checked the inertia switch and it’s fine. I also checked the PCM relay (switched it out with another), the PCM diode (got a reading in one direction but nothing in the other) and visually inspected both PCM related fuses (one in the engine fuse box and one in the cabin fuse box) and all 4 seem fine.
I know the crankshaft position sensor is a common culprit, but I see mixed things online about whether the CEL should be coming on in the on/off position if the crankshaft sensor is bad.
I skipped checking for fuel and spark when I saw the CEL was not coming on. My understanding is that there wouldn’t be either since the PCM isn’t initiating them due to whatever is causing the CEL to not come on.
Other interior lights and instrument lights are coming on (battery, ABS, etc.), just not the CEL. There also haven’t been any intermittent no start or stalling issues other than the weak battery issue the day before.
At key “on”, I do hear a click in the engine that sounds like the relay and there’s a soft almost whine sound that last for a second, but it’s actually up near the battery or front of the engine.
I’m not sure if I’m understanding the interplay between the PCM and the CEL. Any help would be appreciated there.
Any ideas where to look next? I’m going to go ahead and check for spark and fuel because I don’t know what else to do. I suppose I could yank the crankshaft sensor and test it, but it looks like it might be a bit of a PITA to get to.
He was leaving a buddy’s house and it would not start. It had been running fine prior to that. Except that he had just replaced the battery about 24 hours prior due to a low battery that tested bad. Not sure if it could be related, but there it is.
I checked out the Ranger some. It cranks just fine. Strong with no dragging. But I noticed that the check engine light isn’t coming on at key on and engine off. Also, the tachometer isn’t moving even a twitch while the starter cranks the motor.
I’ve tried to do some troubleshooting online which always points in the direction of a PCM issue rather than a spark or fuel issue. I checked the inertia switch and it’s fine. I also checked the PCM relay (switched it out with another), the PCM diode (got a reading in one direction but nothing in the other) and visually inspected both PCM related fuses (one in the engine fuse box and one in the cabin fuse box) and all 4 seem fine.
I know the crankshaft position sensor is a common culprit, but I see mixed things online about whether the CEL should be coming on in the on/off position if the crankshaft sensor is bad.
I skipped checking for fuel and spark when I saw the CEL was not coming on. My understanding is that there wouldn’t be either since the PCM isn’t initiating them due to whatever is causing the CEL to not come on.
Other interior lights and instrument lights are coming on (battery, ABS, etc.), just not the CEL. There also haven’t been any intermittent no start or stalling issues other than the weak battery issue the day before.
At key “on”, I do hear a click in the engine that sounds like the relay and there’s a soft almost whine sound that last for a second, but it’s actually up near the battery or front of the engine.
I’m not sure if I’m understanding the interplay between the PCM and the CEL. Any help would be appreciated there.
Any ideas where to look next? I’m going to go ahead and check for spark and fuel because I don’t know what else to do. I suppose I could yank the crankshaft sensor and test it, but it looks like it might be a bit of a PITA to get to.
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