diff --git a/R/rxsolve.R b/R/rxsolve.R
index 083e507cd..00db8f555 100644
--- a/R/rxsolve.R
+++ b/R/rxsolve.R
@@ -1776,7 +1776,10 @@ rxSolve.default <- function(object, params = NULL, events = NULL, inits = NULL,
       .minfo(paste0("omega has too many items, ignored: '", paste(.ignore, collapse="', '"), "'"))
     }
     .ctl$omega <-.ctl$omega[.w, .w, drop=FALSE]
-    if (dim(.ctl$omega)[1] == 0) .ctl$omega <- NULL
+    if (dim(.ctl$omega)[1] == 0) {
+      .ctl$omega <- NULL
+      .ctl <- do.call(rxControl, .ctl)
+    }
     .names <- c(.names, .col[.w])
   } else if ( inherits(.ctl$omega, "character")) {
     .extraNames <- c(.extraNames, .ctl$omega)
@@ -1798,7 +1801,10 @@ rxSolve.default <- function(object, params = NULL, events = NULL, inits = NULL,
       .minfo(paste0("sigma has too many items, ignored: '", paste(.ignore, collapse="', '"), "'"))
     }
     .ctl$sigma <-.ctl$sigma[.w, .w, drop=FALSE]
-    if (dim(.ctl$sigma)[1] == 0) .ctl$sigma <- NULL
+    if (dim(.ctl$sigma)[1] == 0) {
+      .ctl$sigma <- NULL
+      .ctl <- do.call(rxControl, .ctl)
+    }
     .names <- c(.names, .col[.w])
   } else if ( inherits(.ctl$sigma, "character")) {
     .extraNames <- c(.extraNames, .ctl$sigma)
@@ -1821,7 +1827,10 @@ rxSolve.default <- function(object, params = NULL, events = NULL, inits = NULL,
       .minfo(paste0("thetaMat has too many items, ignored: '", paste(.ignore, collapse="', '"), "'"))
     }
     .ctl$thetaMat <-.ctl$thetaMat[.w, .w, drop=FALSE]
-    if (dim(.ctl$thetaMat)[1] == 0) .ctl$thetaMat <- NULL
+    if (dim(.ctl$thetaMat)[1] == 0) {
+      .ctl$thetaMat <- NULL
+      .ctl <- do.call(rxControl, .ctl)
+    }
     .names <- c(.names, .col[.w])
 
     # now look for zero diagonals
@@ -1831,7 +1840,10 @@ rxSolve.default <- function(object, params = NULL, events = NULL, inits = NULL,
     if (length(.w) > 0) {
       .minfo(paste0("thetaMat has zero diagonal items, ignored: '", paste(.col[.w], collapse="', '"), "'"))
       .ctl$thetaMat <-.ctl$thetaMat[-.w, -.w, drop=FALSE]
-      if (dim(.ctl$thetaMat)[1] == 0) .ctl$thetaMat <- NULL
+      if (dim(.ctl$thetaMat)[1] == 0) {
+        .ctl$thetaMat <- NULL
+        .ctl <- do.call(rxControl, .ctl)
+      }
       .names <- c(.names, .col[-.w])
     }
   }
diff --git a/tests/testthat/test-rxode-issue-349.R b/tests/testthat/test-rxode-issue-349.R
index f23f3be0c..22a636ca1 100644
--- a/tests/testthat/test-rxode-issue-349.R
+++ b/tests/testthat/test-rxode-issue-349.R
@@ -1,14 +1,15 @@
 rxTest({
   test_that("Zero variances; RxODE#299", {
+
     mod <- rxode2({
       eff(0) <- 1
       C2 <- centr / V2
       C3 <- peri / V3
       CL <- TCl * exp(eta.Cl) ## This is coded as a variable in the model
-      d / dt(depot) <- -KA * depot
-      d / dt(centr) <- KA * depot - CL * C2 - Q * C2 + Q * C3
-      d / dt(peri) <- Q * C2 - Q * C3
-      d / dt(eff) <- Kin - Kout * (1 - C2 / (EC50 + C2)) * eff
+      d/dt(depot) <- -KA * depot
+      d/dt(centr) <- KA * depot - CL * C2 - Q * C2 + Q * C3
+      d/dt(peri) <- Q * C2 - Q * C3
+      d/dt(eff) <- Kin - Kout * (1 - C2 / (EC50 + C2)) * eff
       e <- eff + eff.err
       cp <- centr * (1 + cp.err)
     })