What this code means
P0780 indicates a shift error. The first decision in this procedure is which stored code to troubleshoot first. That decision depends on whether P1898 or P1899 is stored at the same time as P0780.
The related codes concern the CVT drive pulley pressure control solenoid valve and CVT driven pulley pressure control solenoid valve. When one of those listed codes accompanies P0780, its troubleshooting takes priority. The code combination therefore determines the starting point for the work.
What the vehicle may do
P0780 can indicate a shift error. This guide uses the accompanying trouble-code information to establish the diagnostic order for that stored condition.
Possible fault areas
The related-code group concerns pressure control at the CVT drive pulley and driven pulley. The priority codes listed by this procedure are:
- P1898.
- P1899.
Read those codes as the conditional priority group described below. Their presence alongside P0780 is what activates the instruction to troubleshoot them first.
Diagnostic path
Establish the stored-code combination
Determine whether P1898 or P1899 is stored along with P0780. Keep the actual combination clear before choosing the troubleshooting order. The procedure's condition is that the codes are stored at the same time.
This makes the rule practical: it refers to the codes found together during the diagnosis. The following examples show how the same priority instruction applies to different combinations of those listed codes.
If P0780 and P1898 are stored together
Troubleshoot P1898 first. In this combination, P1898 is the listed related code that accompanies P0780, so it supplies the priority work item.
The reason for starting there is the relationship stated by the procedure: the accompanying pressure-control code takes priority over the shift-error work. The P0780 code remains part of the recorded condition, while the diagnostic work starts with P1898.
If P0780 and P1899 are stored together
Troubleshoot P1899 first. The same rule applies, with P1899 now being the listed related code present alongside P0780.
Keep the code identity attached to that decision. This example leads to P1899 troubleshooting because P1899 is the accompanying code in the combination being considered.
If both related codes accompany P0780
P1898 and P1899 both belong to the listed priority group. Address their troubleshooting before the P0780 work, following the procedure's instruction for the related codes stored at the same time.
The priority described here is their relationship to P0780: the accompanying listed codes come first. Preserve that relationship when documenting which diagnostic work was selected.
Final check
The outcome of this guide is a code-dependent troubleshooting order. If P1898 or P1899 is stored with P0780, troubleshoot those listed related codes first.
Record the combination that was present and the corresponding priority selected. This keeps the next diagnostic work connected to the actual stored condition and makes the reason for the starting point clear.
