Subject: | DTC P1825 and P1915 set, defaults to 3rd gear start |
Models: | 2008 Buick Enclave |
2008 Chevrolet Equinox |
2007-2008 GMC Acadia |
2007-2008 Pontiac G6 |
2008 Pontiac Torrent |
2007-2008 Saturn AURA, OUTLOOK |
2008 Saturn VUE |
with 6T70/6T75 Automatic Transmission (RPOs MH2, MH4, MH6, MY9) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Diagnostic codes P1825 and P1915 set, defaults to 3rd gear start.
Poor wire welds on the Internal Mode Switch or internal short to voltage in the Solenoid Valve Asm.(w/Body & TCM).
View the Internal Mode Switch signal readings on the Tech II. Compare with the normal readings (example below).
Example: Normal switch Readings
Signal | Signal | Signal | Signal | |
A | B | C | P | |
Park | L | H | H | L |
Reverse | L | L | H | H |
Neutral | H | L | H | L |
Drive | H | L | L | H |
M/Drive | L | L | L | L |
Example: Switch signal readings Low when they should be High. Replace Internal Mode Switch and the Solenoid Valve Asm.(w/Body & TCM).
Signal | Signal | Signal | Signal | |
A | B | C | P | |
Park | L | L | H | L |
Reverse | L _ | L _ | H | H |
Neutral | L | L | H | L |
Drive | L | L | L | H |
M/Drive | L | L | L | L |
Example: Switch signal readings High when they should be Low. Replace Internal Mode Switch
Signal | Signal | Signal | Signal | |
| A | B | C | P |
Park | L | H | H | L |
Reverse | L | L | H | H |
Neutral | H | L | H | L |
Drive6 | H | L | H | L |
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.