Category Archives: Chrysler

2002 Chrysler PT Cruiser P0750 P0888

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P0750 – LR solenoid circuit
P0888 – Trans relay output always OFF
Transmission in Limp Mode

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MIL ON, fault codes always present. Codes return when cleared after key cycle. Both faults indicate a voltage problem. The P0888 can lead you to the cause of both fault codes, so I started there.

First up, go to trans relay and see if it is working. Located in the engine compartment junction box.
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I first went to control side of relay. There no trans relay control signal from TCM. TCM sends 12 volts from PIN 15 (light green) at TCM connector to PIN G4 at trans relay. The relay has a permanent ground on PIN G5. The 12 volt signal to the trans relay was not present. The ground was good.

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With this information I went to the TCM to see if the 12 volt was present. If it was this would indicate an open circuit between TCM and junction box. The 12 volts signal was not present at TCM.

Next up I checked all powers and grounds to TCM. I found PIN 11 (light green / black) missing battery voltage when ignition is switched ON.
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I went to fuse 12 (10A) in fuse block. Voltage was present and fuse was good.
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At this point I ran a jumper wire from fuse 12 to PIN 11 at the TCM. Cycled the key ON. The trans relay activated, no fault codes present.

To go a bit further I located splice S115. Voltage was present. At this point I advised the shop to run a new wire from splice S115 to PIN 11 at TCM.

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A test drive after repairing the open circuit confirmed the fix. No fault codes present and the vehicle shifted normally.

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1995 Chrysler Concorde No Start No Fuel Injector Pulse

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Engine would crank over at a normal RPM. Spark would occur then stop, (intermittent spark). There was no fuel injector pulse. Spark was tested using an HEI spark tester and injector pulse monitored with a noid light.

Once the faults were confirmed I connected my scan tool. In this case a DRB III. The scan tool confirmed my suspicion, the engine was out of sync. See arrow on photo below.
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This video shows what it looks like when cranking the vehicle and viewing the sync data via scan tool data stream.

Next up was checking both cam and crank signals (synchronization) using my ATS lab scope. The pattern below shows an engine that us out of time. The arrow points to a line that depicts (about) where the cam sensor signal (green pattern) should align with the crank signal (yellow pattern)
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Aligning the timing mark on the crank pulley and camshaft sprockets was the final test. The timing belt had jumped a few teeth and luckily this engine is not an interference engine. A new timing belt kit and the engine was running normally.