I think this is what you have. Really close to the description.
DTC P0708: TRANSAXLE RANGE SWITCH CIRCUIT HIGH VOLTAGE
Transaxle range switch determines which gear position has been manually selected. PCM determines this gear selection by detecting a combination of opens and grounds at 4 switch inputs of transaxle range switch. When a switch is open, PCM code input will be high (near ignition voltage). When switch is closed, PCM code input will be low (zero volts). Specific combination of highs and lows (opens and grounds at switch) for 4 code inputs at PCM denote which gear position has been selected. Only one combination is possible for each manual gear selected. DTC sets when all 4 PCM code inputs are high (near ignition voltage) indicating 4 open circuits.
*Condition exists twice in one ignition cycle.
*Ignition voltage is greater than 9.5 volts.
DTC sets when PCM has detected all high transaxle range switch code inputs for greater than 0.5 second.
1.Turn ignition on, engine off. Using scan tool, monitor each gear position while moving gear shift through all gears. If scan tool displays each gear position correctly, problem is intermittent. See DIAGNOSTIC AIDS . If scan tool does not display each gear position correctly, go to next step.
2.Check transaxle range switch connector for tightness. Check tightness of switch to case bolts. If connector or bolts are loose, tighten and retest. Using scan tool, monitor TRANSMISSION RANGE while individually jumping White wire, Black/White wire, Yellow wire and Gray wire to ground. If scan tool displays INVALID as each circuit is jumped to ground, check transaxle range switch connector. If connector is okay, replace transaxle range switch. If scan tool does not display INVALID as each circuit is jumped to ground, repair open in affected circuit or faulty PCM.
***You may not be able to perform the procedure completely without a proper scan tool. But you can check to make sure the Transmission Range Switch is tightly connected and none of the wires are frayed.***
PCM will command second gear starts if this DTC is active.
DTC will set due to a disconnected switch.
Use scan tool to verify that correct gear positions are read.
Check tightness of transaxle switch harness connector and transaxle switch to transaxle case bolts. Each switch ground uses switch case to transaxle case as a ground path.
***Based on your original description, I am leaning towards bad TRS and needs replacing.***
TRANSMISSION RANGE SWITCH. (Sometimes called Position Switch/Sensor)
Removal & Installation
1. Apply parking brake then place control assembly in Neutral. The transaxle shifter must be in Neutral position prior to re-installing the range switch.
2. Remove the shift control cable from the transaxle range switch lever
3. Disconnect the electrical harness connectors from the transaxle range switch
4. Remove the trans axle range switch lever nut and lever
5. Remove trans axle range switch bolts then remove the switch
To Install Using New Switch:
1. Ensure that the trans axle shift shaft is in the NEUTRAL position
2. Align the flats on the trans axle shift shaft with the flats on the trans axle range switch then install the switch
3. Torque the trans axle range switch bolts to 15 lb-ft. (20 Nm)
4. Install the trans axle range switch lever and nut; torque to 26 lb-ft. (35 Nm)
NOTE: After adjusting the switch verify that the engine only starts in Park or Neutral. If the engine starts in any other position readjust the switch.
5. Install the shift control cable to the trans axle range switch lever then verify proper operation
1. Shift the trans axle into NEUTRAL
2. Remove the shift control cable from the trans axle range switch lever
3. Remove the trans axle range switch lever nut and lever
4. Loosen the trans axle range switch bolts
5. Insert the Park Neutral Position (PNP) Switch Tool J41545 then rotate the switch until the tool drops into position
6. Torque the transaxle range switch bolts to 15 lb-ft. (20 Nm)
7. Remove the alignment tool
8. Install the transaxle range switch lever and nut; torque to 26 lb-ft. (35 Nm)
NOTE: After adjusting the switch verify that the engine only starts in PARK or NEUTRAL. If the engine starts in any other position readjust the switch.
9. Install the shift control cable to the transaxle range switch lever then verify proper operation.
I have searched the net for aftermarket part but to no avail. You can only get it at the dealership.
Sunday, May 10th, 2009 AT 2:06 PM